How To Build The Most Energy Efficient Home

How to build the most energy efficient home

I’m going to explain how I would build the most energy efficient home possible, to do this I will not be working off a budget and I will only be using products that are readily available to me. I also will be only using products that I have used before on other homes that I have built. As a company we have been building custom homes for over thirty years and have found the best ways to build homes and some of the products to avoid. I will be relying on this expertise while I explain how to build the most energy efficient home possible.

I will be doing this in parts, breaking down the actual home piece by piece so you understand why I am doing it. I lot of the times it is the little details that make the biggest difference.

Let’s start with how the home will be built.

BASEMENT

Exterior Walls

I would build the basement out of ICF (insulated concrete forms). This is a product that is 2.5 inches of foam on each side of a concrete core that is poured in place. I will be using these walls throughout the entire home, from the footings all the way to the roof line. The standard ICF wall for residential houses has the foam on the outside and inside and then a 6 inch concrete core; I would use the ICF that has a thicker core at least 8 inches. The reason that an ICF wall works so well is that once the concrete core is either heated or cooled by the heating system inside then it stays that way and radiates the heat/cold back into your home. ICF walls resist what is called wind wash; this is when a strong cold wind lowers the temperature of the interior of the wall cavity, this change in temperature affects the inside of your home by making the heating system work harder to keep the temperature up as this new colder air starts to penetrate the walls into the home at a faster rate than usual.

The ICF walls do not require another wall to be built on the inside of them, the foam blocks are all the insulation the walls require, because they are poured concrete you don’t even have to install vapour barrier over them like a traditional wood framed wall. There are also plastic webs that are embedded in the foam block that allow the drywall to be hung off of them.

Because we are using ICF forms we will not even have to worry about having the rim joist of the home sprayed as there is no exposed rim joist on a home that is built with ICF.

Floors

Under the concrete floor of the basement I would place 2 inches of polystyrene foam that is t&ged, this will help stop the cold in the ground from cooling the concrete slab and thus keeping the basement warmer. I would place heating lines in the floor that would be fed from the furnace so that the basement is always warm, once the concrete floor has warmed up to the appropriate temperature it will continue to radiant heat even after the heat lines have been turned off and are not hot. Over top of the polystyrene you would then place your vapour barrier to help keep the moisture out of the concrete floor.

Walkout

The home would have a walkout basement as this allows more livable square feet thus allowing me to have less square footage above ground. It is easier to heat and cool a walkout basement then trying to heat/cool multiple stories above ground that don’t have the luxury of the thermal mass of the ground around them. The walkout would have a lot of windows and doors in it to allow as much natural light in as possible and the home would face as south as possible.

The walkout basement would have frost walls that would be made out of ICF that would give it adequate frost protection and make it easy to heat.

Sump pump

Every home needs a sump pump. Sump pumps can use up a lot of energy if they run all the time. First thing that should be done is there should be a gravity drain installed so that the water that collects in the weeping system has a chance to flow away naturally without the use of electricity. The gravity drain is easily installed with a home that has a walkout as most homes with walkouts are built high on a hill which is the perfect scenario for a gravity drain.

As a backup or as the primary source of power to the sump pump I would install a solar panel on the outside of the home that would power the sump pump. This would allow the sump pump to continue to move water even when the power has failed in the home.

Above grade floors of the house

Exterior walls

All exterior walls in the home would be the 8 inch ICF forms. The outside of the building would be covered in a sustainable product like natural stone. Natural stone as long as it is installed properly will last a life time and also should protect your home because of its hard surface from flying debris, natural stone also has the ability to help keep a home cooler and also cut down on wind wash. Natural stone has no nutritional value in it, this means that bugs do not eat it or wear it out by tunneling into it.

Because the exterior walls are ICF the electrical boxes that are placed into the walls do not expose the wall to letting air penetration in like wood framed walls do. There is no reason to worry about light or electrical plugs needing foam or tape they will never allow a draft into the home.

Roof

I would build the roof so that it is high and steep, this will allow the snow to slide off the roof. I would build large overhangs on the roof. Large overhangs help shade the house against the sun and the harmful UV rays; it also sheds snow and rain water farther from the foundation of the building. I would keep the amount of hips, valleys, dormers and eyebrows to a minimum only having them were needed and not just to make the roof look more aseptically pleasing. I would not have any flat sections or low sloped area’s that will affect the longevity of the roof.

Soffits

I would install aluminum soffits because they will not fade and they have less chance of having
animals or rodents chew on them as there is no food value in them. They are also able to withstand strong winds and flying debris.

Roofing materials

You might wonder why when talking about an energy efficient home I am talking about the roof, well if you were to stick to just asphalt roofing this could limit what you want to do with insulation and air flow as asphalt shingle degrade faster without the proper ventilation below them. Other products like steel or Enviroshake are more forgiving and will withstand a hotter sub structure on the roof.

Home with Enviroshake Roofing

The roofing material itself would have to be Enviroshake or steel depending on where you were building your home. Enviroshake is a product that is made from recycled materials and ethanol waste from the making of ethanol fuel factors. The product looks like cedar shakes but has a 50 year warranty and has the ability to shed snow well. Steel has the same kind of warranty but will shed snow easier then Enviroshake, also if you live in a place with extremely high winds both of these products will stand up to the challenge with steel being a little better. The colour on new steel roofs will last the lifetime of your home not like old steel roofs that were installed on barns that rusted.

Under steel roofs there is a reflective foil product that I would install on the roof; this product helps deflect the heat that can build up under the steel from the sun, allowing the home to stay more of a balanced temperature throughout the year.

Insulating the roof

Insulating the roof/attic space is an art in itself. If you have parts of your home that are cathedral then they should be spray foamed solid between the roof rafters. The amount of insulation that you will be able to install between the rafters will be dictated by the depth of the rafters.

If you have an attic space then I have a very specific way that I would insulate it.

I would not install a vapour barrier on the bottom side of the roof trusses (which is usually a standard in most homes), I would install the drywall first, then on the back side of the drywall (the attic side) I would install a layer of spray foam 2 inches thick right to the back of the drywall covering the whole attic space. Doing this qualifies as a vapour barrier and also acts as an air seal that is far more effective than any other type of insulation. On top of the 2 inches of spray foam I would install blown in cellulose insulation, I would add it till I reached about R-70.Depending on the type of insulation that you use for your blown in will determine the depth of what is required to reach R-70. This exact process of spray foam and blown in will limit the air flow through the attic from the house to the outside world. This has the ability to save you more money on heating and cooling than all the other insulating you can do combined.

Windows

Windows are a huge heat loss to any home. I would install windows that where aluminum skinned on the outside and wood on the inside. The aluminum outside will stand up to the harsh eliminates and having it transition into wood on the inside (I just like the look of wood it being a natural product).

The windows should also be triple pane windows, triple pane will greatly reduce the affect of hot/cold temperatures from transferring inside. On the southern sunny side of the building I would also have solar limiting glass in the triple pane windows and on the northern shadier side I would have solar gaining glass in the triple pane windows. This will help balance the temperature of the house and allow the heating system an easier time at heating and cooling the home.

The windows would be installed with spray foam installed around the window. Because of the depth of the ICF walls it allows me to install double the normal spray foam insulation around the windows insuring the maximum amount of air leakage protection.
One other trick to stopping future drafts around windows is to caulk the trim around the window to the drywall. This is the last measure to stopping drafts from penetrating the home.

Having as may windows as possible that face where the sun will be able to shine in is good because it reduces the amount of energy you have to use with lights but if an area of the home will not receive a lot of sun light then making the windows smaller in that area will help with the heating/cooling demands.

Window coverings

Blinds, drapes and curtains should be used for every window; this is a simple technique to help keep the temperature regulated in the home. If you have windows that are high up and you have trouble reaching them then have them wired for an electrical motor, this will allow you at the push of a button to lower or raise the blinds. The savings on heat/cooling loss will out way the cost of the electricity that is required to run them. A lot of the time windows coverings are more about the comfort of the people in the home then the actual temperature in the home. If you feel colder in a certain room because of the amount of windows then you are more apt to turn on the heat, window coverings limit that problem allowing you to keep the thermostat at a more consistent temperature.

Heating systems

This is the big one, spending the appropriate amount of money on your heating system will save you more money over the long run (using less energy) then everything else I have talked about.

I would install a geothermal heating system. The geothermal heating system would be a dual system that would allow it to supply in-floor heat and also air heat to the duct system. Geothermal works by absorbing the heat/cold from the ground and transferring it into the home. I would install either the ground loops or install the loops right into a large body of water (lake, river, and ocean). If I didn’t have the room then I would opt for the drilled well (vertical loops) variety.

All the floors in the home would have in-floor heat; every room would be on its own zone. This would allow me to turn down the heating in any room that I wasn’t using saving on energy. This would require thermostats in every room of the house.

I would also install ductwork throughout the entire house for the furnace to supply cooling throughout the home as in-floor does not have the ability to supply cooling. This duct system would also be used to supply heat when needed; in-floor heat can take a while to warm up a large slab of concrete to radiate heat, this way you would have a way to immediately heat an area up. This would require that all the thermostats in the home are smart ones and be programmable. I would then install electronic low voltage dampers; these will allow the furnace to only heat individual rooms instead of whole areas of the house. This really comes in handy when cooling the home, the southern side of the house will be hotter than the northern side so using more energy on one side and less on the other will help balance the environment of the home. Less energy is used for the overall heating and cooling this way and the house is kept at a perfect temperature everywhere you go in it.

The thermostats in the home would all be linked through the internet so that I could adjust the home temperature from my phone or computer anywhere in the world allowing me to lower energy use when it isn’t needed.

I would have multiple hot water tanks installed; the great thing about geothermal heating is that it supplies you with almost free hot water. The first hot water tank would be pre-heated (for free) by the geothermal system and then the second hot water tank would keep it at a constant residential appropriate temperature until it is used.

An HRV in the home is a must; this recycles the air in the home reducing the need for a lot of air to be constantly brought in from the outside. I would install what is called a complicated HRV system. This is a system that has ducting running to all bathrooms in the home, not just the normal furnace returns. The ducting that is run to the bathrooms will remove the moist hot air from the bathrooms and feeds it through the HRV system instead of the typical ceiling fans that are usually installed. This limits the amount of penetrations through the outside walls and is also more efficient then using the fan system in each individual bathroom. The bathroom fans only have a small piece of metal between your home and the outside world, with enough air pressure from outside cold air can penetrate into the home.

Auxiliary heating

I would install at least one fireplace, they should be wood burning. The most efficient fireplaces are hand built Rumford fireplaces. These allow you to place wood vertically inside the fire chamber and also will allow you to have a fire in above zero conditions. If you don’t have the room for Rumford’s then sealed fireplaces should be installed. These will have doors on them so that there isn’t any way for a cold draft to work its way into the home.

Having fireplaces can cause a little bit of heat loss when they are not in use but the benefits far out way the negatives.

Having fireplaces allow you to warm up an area of the home without having to use the heating system. Burning wood is a natural thing and is not harmful to the environment, especially if you are not heating your entire home with it. It is also a great backup if the power fails and you require immediate heat, it doesn’t need gas or oil to keep going and will work no matter what type of weather is outside. A fireplace can keep your home warm and safe for as long as you need it too.

Lighting

I would install low voltage LED pot lights throughout the home. These lights use such little power that all the low voltage LED pot lights in a large home equal out to a couple of normal halogen pot lights. Any other lights that you install should be at minimum some form of LED lighting.

Lighting should all be wired to smart controls, this will allow you to access the lighting via internet so that lights do not have to be left on at all times. This will also allow you to control all the lighting when you are in the home, when you go to bed you can hit the command to turn off all the lights and any light you forgot to turn off does. This is a great feature if you have children who like to leave bathroom or closet lights on after they are done using them.

Dimmers should be installed on all lights, this limits the amount of power that the lights will used especially if you are using them as a night light or accent lighting or for security purposes when you are not at home.

Ceiling Fans

In any room that has high ceilings you should install a ceiling fan, this will help the heating system reuse the air that can get trapped in the high ceilings of the home. It also helps in the summer to move air helping limit your need to run the air conditioning.

Appliances

All the appliances should be energy star or better rated appliances. You should only have as many appliances as you require. For example: if you have two or three refrigerators and they are all partly full then you are wasting energy by having all of them plugged in and running.

You should have a cold storage room in the basement that will be cooled naturally requiring no electricity for those types of goods. The wall between the cold room and the rest of the house will require an ICF wall and an insulated steel door to keep the cold from penetrating the home.

Well and water

Your well pump should be a constant pressure pump. This kind of pump keeps water pressure constant in the line from the well to the home all the time. This allows a smaller pressure tank and also for the pump to work less frequently saving you money on electricity.

All taps, toilets and plumbing fixtures in the home should be low flow or low water use. Modern plumbing fixtures that use less water are engineered in a way that you should basically not notice that less water is being used. It will save on your well pump being used and the amount of liquid your septic system would be required to handle.

Options for you

You could install small scale wind and solar panels to offset your electricity use. I would not try to rely only on this power source to run a whole house, the electricity needed to run the heating system will probably be more then the renewable energy generators are able to create without taking in the need of the rest of the home. What you can do is have a transfer switch that you could flip when the power goes out and you would be able to power parts of the house without using a generator.

The other thing you could do is have the wind and solar energy feed the grid (you being compensated for that) offsetting any electricity costs that you use and still use it as a generator when the electricity grid goes down.

You can also install a system that in low electricity times of the day or year will run your entire home off the solar and wind, it then kicks back to the grid when you require more electricity as your usage and demand throughout the day changes. This would also help offset your electricity bills.

In conclusion

You now have the most efficient energy saving home possible, all of what I have mentioned is being used today in residential construction, like I stated at the start I have designed and built this house using no budget. A lot of the items that I have mentioned are expensive but they do work as energy savers. You do not have to use them all to save energy (because of the cost most people do not) but using some of them will help you save money in the long run and help keep those energy bills and your consumption of resources to a minimum.

Rob Abbott
Village Builders Inc.