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First Aid for Home Owners.
by Hakan Falk, "Energy Saving Now"
We often get the question "I have a poorly insulated home, what can I do to improve it?", it is implied that the improvements should be very affordable, not need major construction work and be effective. There are many things that can be done, but I have collected some obvious and very effective actions that I call "first aid for home owners". It includes a set of cost efficient actions, that together can lower the energy use with 50% or more, it is at least what I have done. It also, in some parts, describes what I done with my present home. With larger remodeling and changes, a further 50% is possible, only by thoughtful choices and in this case the home will at the end fulfill the suggested EU Building code. You can find some guidance in an EU investigation and my suggestion "Thermal Building Codes for developing countries". I also did some comparisons with Spanish and Nordic homes, which indicate quite well the possible gains.
We often say that energy savings in buildings take a long time to effect a country's energy consumption and mean by that changes in Building codes and basic construction principles. There are however very much that can be done in much shorter time frames and the following are a collection of measures the will have significant impacts.
Attic insulation.
Most homes have access to the attic space and to introduce or improve the insulation there is both easy and very economical. It is the single most efficient improvement (if needed) that can be done and should control air flow, heat transfer and optionally radiation/emission. A typical improvement consist of the following steps,
- Remove existing insulation.
If there is any insulation, it has to be removed. If it is suitable, it can later be used as a part of the thermal insulation.
- Vapor (and radiant) barrier.
Nearest to the ceiling of the room below, a vapor/air barrier is placed. In its simplest form, it is plastic sheet as the ones used on construction sites and in foundations. There are sheets that also includes low emission properties radiant barrier as well as vapor control, they cost a bit more. If it is a matter of money, I rather see an interior low-e paint than low-e barrier wrap in the ceiling, best is maybe both. It is not very large costs anyway. The major function of the vapor/air barrier is to prevent air infiltration through the ceiling. This save a lot of energy since the warm air is the carrier of the energy in first place.
- Thermal insulation.
Thermal insulation is placed on top of the vapor/air barrier. It should be or correspond to minimum 20 cm (8 inches) and maximum 40 cm (16 inches) mineral wool. To do less is not enough and to do more give no real value.
- Radiant barrier. (Optional)
As an enhancement in warmer climate, a layer of low-e Aluminum flakes can be applied as radiant barrier on top of the insulation. I is however very important the it is not stopping vapor to pass. It will help to lower the energy need for air conditioning during periods of strong sunshine.
Radiant barriers are more and more becoming a part of insulation techniques. It is an easy technique and based on reflection the infrared parts of the heat spectrum. Since heat originates from this spectrum (radiation from the Sun), it is in many cases quite effective. To heat the air is an indirect process, the infrared needs to first heat up a material, who then in its turn heat up the air. This means that the material must be able to absorb the infrared spectrum in the first place and its capacity to absorb is defined as the emission factor.
The lower the emission factor is the less will be absorbed and the larger is the reflection of the infrared heat. The way that the building industry is using materials, mirrors the very narrow view of restricting the infrared spectrum form either entering and leaving the building construction. It is much more to this, when you look at how the human body controls its temperature, but the current engineering practices are more geared towards designing dwellings for "air thermometers" than for humans.
- Attic ventilation.
The attic above the insulation must be well and efficiently ventilated. Normally this is achieved with several openings at different directions of the home. Any failure in sufficient ventilation, will result in humidity problems.
As mentioned, this is the single most important improvement that can be done and at the same time the most cost effective. It is not uncommon that you will find it paid back within the first year, if your starting situation is an uninsulated attic. You will also get rid of those icicles, that you have in a poorly insulated home.
Wall improvements.
Wall thermal insulation improvements are usually more elaborate and costly. It is easy to make mistakes which result in humidity with sometimes fatal results for the building. It is not included in my preferred first aid kit. Partial improvements like windows, doors and leakage are very efficient, as well as manipulation of temperature/emission factor of surfaces. The lower surface temperatures are best compensated by modifications of Heating, Ventilation and Air Conditioning (HVAC) system. This will result in specific actions, each one cost efficient on its one.
- Sealing of air leakage.
Together with attic insulation and window improvement, the sealing of air leakage is one of the most apparent and cost efficient actions.
Some years ago, we were involved in simulations and experiments of a project that in translation could be called "Insulation by reverse air infiltration" or "Reverse infiltration insulation". The ideas behind it was that by controlling the air tightness of a room and build up a vacuum with evacuation fans, the fresh air would pass the construction materials and be heated up by the outgoing heat losses. This way we could use the construction for heat recuperation and also use stored energy. The results was promising in controlled test environment, but after field test it was regarded as too complicated and difficult to achieve and maintain. It proved however the known large savings, which are done with sealing of leakage, are very significant and the method in right conditions can give positive effects. Under HVAC improvement, we will come back to this.
The weakest points are around windows and doors. Applying adhesive rubber profiles between window/door and window/door frame is a commonly used method. The next largest is leakage between window/door frame and construction and is fixed by removing covering list work and seal with mineral wool and then remount list work.
We do not consider introduction of "wind breakers", "vapor barriers" or injection of insulation foam, as suitable "first aid" actions in wall constructions. Such improvements have to be done by people who really know what they are doing, otherwise it could be fatal for the home construction. We also want to warn about that many experts that is working with this, not necessary have the needed knowledge and understanding. It is therefore important that the contractor can show that their work is covered by sufficient insurance, that protect the client and will survive any future problems with the contractor.
- Window improvements.
Window improvements are essential for both economy and comfort. It is very appreciated by the dwellings inhabitants and maybe more by "the humans" than the "air thermometers".
It is all kind of opinions of the effects of improving window insulation. "The thermometers" claim an insulation of hot air, but the humans perception of improvements are higher than the R-values would indicate, so the humans claim a significant comfort improvement. Looking at what is happening with a window and what effects that are generated, we find that the major parameters are the R-value, the surface temperature and the emission factor. It is also an effect, often referred to by HVAC engineers and that is air movement or downdraft as it is normally called.
Investigations of downdraft is dependent on the surface temperature of the window. For a single glass window the air movement start at 8 degree C outside temperature, double glass at 4 degree and triple glass at 0 degree. This is dependent on the surface temperature of the inner glass. It is also an important factor for the humans who is sensitive to the surface temperature, the "air thermometers" are not. With a higher surface temperature the humans need a lower air temperature to compensate and by that energy is saved. An other way to compensate is thru a radiator close to the window and with higher surface temperature, then radiator need less surface temperature and energy to compensate for window surface temperature.
It is also possible to work with the emission factor and mount a low emission (low-e) glass as outside glass. It will be easier to maintain the body heat and the surface temperature on the inner glass will also go up a bit. Limiting the radiation losses from the body, will allow for lower air temperatures and energy savings.
Changing a single glass window in a wood frame to a double gas or vacuum filled insulation glass window is not an expensive exercise. Neither to change the outer glass in a double frame and double glass window, to get the out side glass as a low-e glass adds a bit cost but is still good economy. The result is guaranteed lower cost and better comfort.
To change the whole window and frame is cost efficient when replacing single glass windows. Replacing double glass to triple glass is not one of the first things I would do. I would wait for a major remodeling in this case.
- Outside Window shutters.
In the countries around Mediterranean Sea and Southern Europe (I also belive Central and South America), it is very common with Window shutters on the outside of the window. Outdoor shutters are normally louvered, but having solid shutters on hinges is not uncommon. In Nordic European countries, this is normally a louvered shutter, located between window glasses. It has its roots in ancient building traditions and much thought are not given to its importance and function as energy saving technology. The reason it is worth mentioning, is the wide unawareness of the savings that can be done with this. It is even quite common to mount shutters on the side of the windows as decoration, but they are not possible to close. Quite an amazing proof of the opposite to development, to express it in a nice way.
The traditional use, before the energy age, was to use shutters a control system for storing solar energy. In the summer, the shutters would be closed to minimize the heating of dwelling from the sun and night time they would be open to maximize losses of energy to the dark outside. In winter it was the reverse, they would be open during the day to maximize the incoming energy from the sun and closed at night to minimize energy losses. If you are looking for savings in energy and costs, why not develop some good ancient habits.
- Door improvements.
Entrance doors are a bit more difficult than windows, because of their size and function. Well insulated entrance doors must be done both with considerations to security and insulation. The Swedish Building code prescribe minimum insulation values. Added to this is also a quality demand, which prescribes that they should have a construction that ensures full long term functionality at a prescribed temperature difference between outside and inside temperatures. The minimum standard is 50 degree Celsius temperature difference added to the insulation standard.
In colder climates it is very common that the entrance have double doors. Either with a separate entrance space or with a normal room dividing door mounted in a frame directly inside the outer door. If you have double doors, it is not necessary or feasible to add insulation. If you have an entrance space, often combined with storage, it can be feasible to improve the entrance door anyway.
The most obvious is to always see to it that the seals between frame and door are functional. If the door does not have efficient rubber sealing it should be complemented with such. In some countries, it is common with mail openings in the door and they should be of the type with flaps both on outside and inside.
It is difficult to add insulation to entrance doors, because the frame and hinges are often not dimensioned for the added weight of additional insulation construction. The result is often that after a while problems occur with the functionality of the door. To mount added insulation need reinforcements both of the door, frame and hinges. To add insulation becomes both elaborate and costly, if done correctly. Therefore it is better and often cheaper or the same cost, to add a door on the inside
Because of security and protection from dirt, rain and snow, an entrance door, if correct, always opens to the outside. If it does not, it is a design mistake and we assume that they are not common. It is therefore reasonable to assume that almost everybody can add a frame construction, with space between them that allow for door handles, and an inside door to a single door entrance.
- Fireplaces, Attic entrance and other.
It is some very large points of energy waste, that are not always obvious and sometimes forgotten. Open Fireplace or other fireplaces with chimney must have chimney closure when not used, they are otherwise very energy wasting, the preferred design should be closed fireplaces with separate air intake form the outside. Attic entrances are often uninsulated, poorly sealed and causes large energy losses, they should be sealed and insulated at the same standard as the rest of the attic. Duct work for ventilation should be controlled and if needed sealed and insulated. All these point are cause of large energy losses, but are easy and cheap to improve. It might also be others that I have not mentioned, who deserves to be checked and improved.
- Painting with low-e paint.
A materials capacity to absorb infrared radiation and as a result be heated up is called the emission factor. The range of the emission factor is between 0 and 1. Low emission factor means a high reflection and high emission factor mens a high absorption. More than 90% of normal building materials have an emission factor over 0.8 and absorb a large part of the radiant heat, like solar. The building industry starts slowly to learn and understand radiant barriers as parts of constructions, maybe because that it can be related to air temperature. One day in the hopefully not too distant future, they might also learn about humans.
All living systems on earth are dependent directly or indirectly of radiant heat from the sun. The human is also using radiant heat as described in "Make it comfortable for real People"
. It is quite easy to test, if you go out to the kitchen an cut a piece of kitchen aluminum sheet that is larger than your face. Push the sheet first to your face, so it take the same shape as it, then hold it a couple of centimeters from your face. You will feel how the face get warmer by the reflection of your body heat. It you the go out in the sunshine and place yourself so the sun can reflect in the sheet and to your face, the effect is very noticeable. You can also wrap sheet around your arm and feel how it rapidly get warmer.
Low-e (low emission) paint is a patented German invention by IPS Innovative Products & Systems, licensed to Chemrex in US and called Radiance and a part of the Degussa Group. In simple terms, it is a paint were the usual additive titanium have been replaced by aluminum and that way acquired low emission properties. It does not take much phantasy to recognize the very large importance this innovation can have on energy use in buildings. If you paint 100% of the room surfaces and do not have any shadowing items etc. the theoretical energy saving would be around 30%. The reality is different and practical results from real environments show conservative results around 15% energy savings.
In looking at availability of information on Internet, I stumbled on one of the most blatant corruptive examples for a long time. The Canadian Competition Bureau lend them self to make a ruling of that statements of effects from low-e paints must be limited to 5% savings. The ruling that have no base in either science nor from practical results, only serves the goal to protect the established paint industry from fair competition. Which is the total opposite of its officially declared purpose and is against the social and economic interests of Canada as a country. I was amazed, but not surprised, this things does not surprise me any longer.
HVAC systems and modifications.
Changes, methods and settings in HVAC systems can be very easy and small, with effects that often are large on consumption. Most HVAC systems today, was designed and have developed practises from the time when energy was very cheap. Everybody believed that it would last forever and it was cheaper to do it and make large over dimensioning, than learn to think and calculate. Mistakes are not done deliberately and there are not any malicious conspiration behind it. There are however resistance to change to more correct thinking, mainly because of the drop in corporate revenues and profits that maybe would be the consequences. Examples on causes for the large energy waste are,
- An almost fanatic belief in the effect of air temperature, as a single description of comfort and dimensioning factor for construction, equipment and control policies. The use of air temperature remind me more of religion, than engineering.
- Use of inadequate and faulty calculation methods for dimensioning of energy need and the effects this have on dimensioning of equipment and control methods.
- A lack of understanding of the movement and transformation of energy. Which leads not only to neglect of factors like emission and storage, it also causes large energy use to be able to neglect these factors. As decribed in,
Ancient AC units or, humidity is more important.
- A nearly total disconnect to how humans functioning in the environment and what is important.
We could do a very long list, but the above items are major and very important. It also result in a large need of corrective actions, that can be spectacular in energy savings. It is however not easy to know what is best in every single case and general advices are not always applicable. I am however listing some possible actions in my "first aid" and they are based on the most common and systematic faults in current thinking.
- Radiator systems.
If you have a radiator based heating system, you can try some simple actions to improve the functioning. As a background for this, please read "Radiator mess! Radiator design and use", because it helps if you understand your situation. The ideal heating is a radiant system based on low temperature as heating medium. Sample of this, are radiant floor or large radiant radiator surfaces. A low temperature system maximize the flexibility in choice of heating source and minimize losses, at the same time as you get the best interaction with the human body.
In our home who is subject to "first aid", we are assuming the now most popular and common radiators of convection type, correctly placed on out side wall and under/near windows. We also assume that radiators are over dimensioned in its capacity to produce warm air, since this is the common case in most installations.
Over dimensioning of hot air production in combination with thermostats that regulate feeding of radiators by on/off circulation, will generate a recognizable pattern similar to what we describe in "1973 the year of the first serious energy crises". When the room thermostat reaches set temperature the radiator shuts off and even if the room temperature changes slowly, the radiator cools down faster. When the surface temperature falls it will loose its capacity to compensate for the cool surface temperatures on windows and walls, even if the room air temperature has not fallen enough to turn the thermostat on. The inhabitant start to freeze and will turn the room thermostat on a higher value. After a while the room thermostat will be set around 22 to 24 degree Celsius. With such a high room temperature the energy waste will be between 15 to 25%, compared with a properly dimensioned radiator and system, that will deliver constant comfort at 20 to 22 degree Celsius.
If the radiator is not correctly placed, it can somewhat be compensated by low-e paint and low-e windows. What we want from the radiator is the following,
- Constantly maintain radiant surface temperature, enough to compensate for low surface temperatures on windows and outer walls.
- Produce warm air to keep a desired air temperature, without reaching a stage were the radiant heat will fall too much.
If the described problems of high room temperature and the sensation of variations in perceived temperature can be noticed, significant energy savings can be made by rising the radiant surface and restricting the production of warm air. This also reduces the capacity in a positive way, the radiator will keep its surface temperature longer and provide for both better comfort and energy savings.
The good news is that this can not only be done cheaply, but can also easily be tested before making changes permanent. I am quite sure that the average HVAC engineer is against it and equally sure that he does not really know why, but I suggest the following modifications and test them in the room where the thermostat is located,
- To test in the room where the thermostat is, cover the top and one third of the radiators back and front with kitchen aluminum sheet. Also place a piece of wood on the top of radiator and close to the wall, as it you had a closed shelf above the radiator. Test it during a normal cold period, because the permanent solution will be better and cover the coldest periods without problems, if the test works well.
- Subject to a successful test, you can mount a more permanent radiator enclosures. You can either buy them from a supplier like www.radiatorenclosures.com or you can make them yourself. Suppliers of radiator enclosures often try to explain their better performance with some kind of air distribution theory But the waist of the body is often the least active part in maintaining the body temperature, the head/hand/feet are the most active and sensitive. Have fun because now you know better, because you understand how the human body works. The improvement is however used for lowering the room temperature and will give 10 to 20% energy savings. One important feature to add a back to the enclosure, is a board with aluminum sheet, as big as the radiator enclosure, between the radiator and wall. If you have space, make the enclosure as much wider than the radiator as you can, to extend the radiation surface, often you also get a positive decorative effect by doing so. It is difficult to find other means of correcting over dimensioning and mistakes in choice of radiator types, than by radiator enclosures.
- After applying the radiator enclosures, the system must be adjusted and balanced. On each radiator you should have two valves, one at radiator entrance and with a knob for individual adjustments and one at the radiator exit with covered adjustment with screwdriver. The latter is used for setting a balance with the rest of the heating system. You set the knob valve on around 2/3 open and adjust the radiators to a level where you can just about feel the difference between entrance and exit. Since you have the advantage of time, which an installer normally do not have, you can later adjust it to how the individual rooms react. This way you balance the distribution in the system.
What is described are easy and not costly actions, with significant improvements in comfort and energy savings. In our opinion they well meet the criteria for "first aid" actions.
- Forced air heating/cooling.
Forced air heating is a hopelessly inefficient heating method by itself and it is difficult to improve on. Forced air cooling is more efficient, if you think about thermodynamic. For heating we are struggling to contain the heat and minimize escape, but for cooling we want to avoid heat and vapor from entering. It does not need much engineering knowledge, only a bit of logic, to understand that combining heating and cooling in a forced air system, result in a lot of energy waste. If you then combine it with ventilation as most are, which is introduction of fresh air, you really made it as difficult as it can be. Some things can however be done to ensure that it works as good as possible,
- Seal and insulate the ducts very well, since they are under higher pressure/vacuum and an air flow sweeping the surfaces, they are extremely sensitive to energy losses in the duct system. Any weaknesses in the duct system gets multiplied by the way the system works. Apart from air tightness and a thick insulation, a reflective low-e wrapping of the duct insulation will help and is often suggested by HVAC engineers.
- Close the ventilation part, so the system becomes a pure recirculation system.
- Make a separate air evacuation system with evacuation points in kitchen, cooking ventilator and bathrooms. Use combined evacuation, warm water with heat pump with energy recuperation from the evacuation air, which in around 5 years will pay back the investment. The idea would be to create the possibility to some limited benefits of the principle of "insulation by infiltration". See more under heading "Ventilation".
Since the performance of a "Forced air system" can show dramatic variation in energy use, only based on the above points, it is difficult to quantify general saving possibilities.
- AC/heat pump units.
This is a very important subject that need special attention, see our article "Dimensioning and use of AC/heat pump units". If you have or planning to get AC units, it is now possible to acquire ones that are up to 30% more energy efficient, than the commonly used fixed speed ones.
- Temperature control.
The most commonly used thermostats have a difference of +/- 0.5 degree Celsius or +/- 1 degree F air temperature. Change thermostats to programmable ones with adjustable range and clocks, minimum double the range from the common. If you cannot find adjustable thermostats, buy an additional one and connect them so one is controlling the on and the other one the off. This will allow for better adjustment the buildings emission/storage properties and especially important in combination with previous described improvements.
It would be better if we could operate equipment with the Effective Temperature instead of air temperature, but we are not there yet. It is not difficult to make sensors, the problem is more one of following modern engineering tradition, instead of reality.
- Ventilation.
Always use a separate air evacuation system with collection points in kitchen, stove ventilator, bathrooms, garage and other spaces of similar characteristics. In the Sweden and the Nordic countries, a now popular appliance is an evacuation unit about the size of a fridge. I contains evacuation fan, heat pump compressor and hot water deposit and uses the heat pump to warm water with the energy in the warm evacuation air. The ones I have seen are from the Electrolux group and pays off in 5 years for a normal family.
- Operating policies.
Wether you are a home owner or a large site, you benefit from thinking through how the equipment should be operated and in what way it can be adopted to seasons, environment, construction, emission factors, storage and user habits. It can be supported by complicated control equipment, based on narrow air temperature and enormous energy waste, or simple sensors and timers that are efficient. For the normal home owner it is more a question of habits and how and when they use the equipment, rate schemes are in all cases an important factor.
To exemplify operating policies for a home owner, it might be best to describe how I am operating my home. It is the second home I have in the same area in Spain. The first one I bought 1984 and used as vacation place until 1993 when I moved to Spain. That one I completely renovated 1985, with heated floors and most of the improvements mentioned in this article. Despite its large size (1,100 square meters) the energy use was like a 250 square meter traditional Spanish home. 1995 we decided that it was too big and sold it, to be able to buy an other home in the same area. It was half the size, but also had a separate apartment with garden and pool, which we rent to people on vacations. This home was already renovated, but without any thoughts on energy efficiency. We have done several adjustments, again described in the article, and are now using less than 40% of the energy that was needed the first years. Our 6,000 liter oil deposit, that in the beginning lasted for less than a year, now last 2.5 years and also saved significant money in the possibility to plan purchases to current market price. The electricity consumption has been unchanged.
Energy prices are volatile but roughly the oil is around $0.16 kWh and electricity $0.24 kWh. I have electricity night rate at 40% discount between 24.00 to 06.00 and it put electricity at same level as oil. I have a burner/boiler with 90% yearly average efficiency. Using heat pump at season with over 8 degree Celsius temperatures give a price of $0.08 kWh during daytime and $0.05 kWh during night. My main heating system is radiators and for summer I have AC-units with heat pump. The warming with warm air, is around 60% to 70% efficient compared with radiators. Hot water production is solar panels, with additional resistor heating (for backup) in deposit (200 liter, which need to be extended to 400 liter) and going through the oil burner/boiler for maintaining a continuous hot water supply at 60 degree Celsius by a mixing thermostat. Additional large electricity consumers are pool equipment and my on line computers.
It is three distinct operation scenarios for winter, fall/spring and summer.
- Winter
December - March is the winter season and my sole heating source is oil. The solar panels contribute maybe with around 20% of hot water production. Heating is maintained continuously at set temperature. I do not use lowering of temperature during night, since it is nearly no gains and negative for comfort.
- Fall/Spring
April - May and October - November is roughly the seasons and the heating is a combination of oil and heat pumps during night rate. I do not use lowering of night temperature, since I want to accumulate the cheaper heat from heat pumps and minimize the need of heating during day time. Solar panels contribute with 60% of hot water.
- Summer
June - September is a period when heating is not needed. Solar panels contribute with 80% of hot water and could be 100% with additional deposit. I am using a 2 to 3 degree Celsius lowering of night temperature for AC-units, to remove stored heat at low tariff and prepare the home for next day. The lowering of night temperatures is good for sleeping and save day time energy for cooling. This work especially good for the new AC units with variable speed compressors.
I never use lowering/rise of temperatures if I only go away for a 24 to 36 hour period. It is no or small gains in doing that, only affects comfort negatively. If I go away for 2 to 4 days, I can turn down heating with 3 to 4 degrees Celsius and turn off cooling. Longer periods, I will turn off systems and arrange that somebody turns them on 12 hours before I return. I will always turn off ventilation system, if I leave for more than a day and turn it on when I come back. This give significant savings and can be done on a daily basis if the home is not occupied.
Lightning and Appliances.
Something that already had a major impact on energy use is the use of CFL lamps. The cost for them are now going down to levels that make the normal light bulbs obsolete. I am using CFL everywhere, except for some decoration and painting illuminations, where the color spectrum is important. Not for myself, because I have. like most men a slightly defect color seeing. It is for my wife, that like most women have a perfect color seeing. Sombody explained that this was that the women have two of the same cromosomes and it is very unusal that both carry a color seeing defect. Men who have two different cromosomes, only have one chance of having a perfect color seeing and therefore defects are more common.
It is worth mentioning the effect that the furniture chain IKEA had on sales of CFL lamps in Europe. Years ago they decided to sell CFL cheap in their stores and it is now a very important attraction for customers. They are selling CFL at half to one third of the price in other stores. IKEA is a foundation, govern by the employees and is involved in quite a number of charitable activities, being the largest in the world on furniture and home decoration, they already had quite an impact on energy saving.
Hot water production.
Solar panels for hot water production is one of the best investments available and it is remarkable that not everybody who can, have it. It is paid back in 3 to 5 years, which correspond to around a 20% interest. The life span of equipment is 10 to 20 years. I know of equipment that is 25 to 30 years old and still working fine, saving energy and money for their owners every day.
Hakan Falk
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