Home remodeling for energy efficiency: prepare for rising heating costs
|A complete gut job will result in a more beautiful and efficient home…Eventually!|
If you’re considering embarking on home remodeling for energy efficiency, think “energy savings” as a strategy. Energy efficiency perhaps isn’t the most interesting aspect of a home remodel, but it is a crucial issue.
Let me make an analogy to a car: Many car owners want to do the fun maintenance to their car, like installing a new set of shiny tire rims or a new stereo system. But most often, their money would be better spent on having their timing belt changed and a new water pump put in. These seemingly mundane maintenances are what keep your car on the road; without their proper function, you have no transportation.
When maintaining your home, think “function first, aesthetics second.” That is certainly not to say that some interesting architectural changes can’t happen in the remodel; some functional changes are connected with aesthetics and energy efficiency. Real-estate appraisal is gradually moving towards valuing homes in energy efficiency. This sort of home-valuing is a bit behind the times, but is slowly moving towards estimating a home’s worth not just by square-footage and number of bathrooms.
Most all scholars and analysts agree that we are now past Peak Oil and that fuel prices will exponentially rise. As we continue to turn past the apex of Peak Oil and start running into the next phases of oil depletion, many of the energy sources that we rely on now, like electricity and natural gas, will become more expensive. The current system of harvesting and refinement of energy sources relies on cheap oil. Everything from the manufacturing of new oil wells and electrical plants, the transportation of energy, and the installation of a heating system into the home all rely on oil. This point made, lets look at your home. How we can tighten down on home fuel consumption and save you money?
When remodeling with a focus on energy-efficiency, first look for leaks. Air infiltration is one of the primary areas of concern when trying to achieve tighter efficiency in the home. Windows, doors, venting, and crawl spaces, are the easier areas that should be targeted. A cold, windy day is a good time to look for air leaks. Simply put your hand up to doors and windows- if you feel a draft, you have found a problem. This image shows barnboard gaps filled with foam insulation to seal against air infiltration.
When looking for replacements to your old doors, choose quality, modern exterior doors that come with triple locks (locks on the top, middle, and bottom of door). These locks make a huge improvement on getting the door gaskets to seal completely. Old wooden doors are tall and not very thick; it is common that this type of door will bow end to end along the locking side. The only way to take the bow out of the door is to pull on top, middle, and bottom, allowing the door to fully seat against the gaskets. If you have an old, architecturally elegant door that you just can’t part with, installing a storm door over the old door will help create an air space and should reduce air infiltration.
|A modern, double-hung window installed to meet historic district regulation may be expensive, but will be a huge energy improvement in the long run.|
|New thermal pane 6×6-
a custom-built historic model
Replacing old windows or installing them in new locations can result in both energy and aesthetic improvement. Properly positioned windows allow natural light into the home and can help ventilate the home without the use of electric fans or air conditioning, saving you money. Windows also can allow for solar gain to occur- a source of free heat. Replacing old windows can result in huge energy savings. Old, single pane windows have very little insulative value, whereas modern glazings create resistance to air temperature change by having an airspace between panes and light filters. Most old windows have no insulation around their perimeters, allowing for air leakage. Modern windows typically have better seals and gaskets, are foamed into their hole, and are installed to be water-tight.
|Framing in new windows|
Adding insulation to your home is another way to improve energy-efficiency. In old homes, installing insulation can be tricky; each old home has its own set of battles in retrofitting new insulation. Roofs must be insulated properly as heat rises and will exit here, however, old homes typically have little to no roof insulation. Before the development of modern insulation, old buildings were designed to have an uninsulated attic that created an airspace between lower living spaces and the outside cold. The attic was not meant as a living space- it was too hot in the summer and too cold in the winter. Historically, the attic was used as storage space, however, many attics today used as bedrooms.
|Retrofit insulated attic|
In many old attics, there is often not enough head room for lowering ceilings and add the appropriate thickness of fiberglass batten insulation and required vent space. Vent space is critical because it prevents damaging condensation from occurring, which can destroy interior materials. In Bozeman, Montana, the modern energy codes require vaulted ceilings to meet R-38 and flat or truss ceilings to meet R-50. For these reasons, uninsulated attics are usually retrofitted with modern rigid insulation or sprayed foam, the latter of which has better performance, but is more costly. (Read a past blog entry about insulation here.)
|Old roof off|
|New third floor and properly insulated roof|
|Bye-bye dark, cold attic|
|Old attic became a new 3rd floor|
In some cases, it is better to completely remove the existing, uninsulated roof and reconfigure it to create a usable space. By remodeling the attic into an additional floor, you can achieve interesting, high-up views as well as appropriate insulation and venting. I remodeled a home in Portland, Maine (see write up here) where the existing attic and roof were completely removed. A new shed roof and floor system were built, creating a beautiful and spacious third floor. What had been a dismal, cold attic with no views became a penthouse with decks on each end and amazing views of Back Bay.
Insulating walls is another important home energy improvement. There are many ways of insulating walls, which are usually determined by the home’s existing wall type, such as 2″x4″ or 2″x6″. When assessing a home’s remodeling and insulation needs, I ask the questions like, “Is your exterior siding in need of replacement?” “Do you want new interior wall surfaces (drywall, plaster) because the old walls are rotted out or falling down?” There are different strategies depending on your home’s condition. Assuming that the exterior walls are already insulated, one strategy to increase your wall insulation performance is to add furring strips and rigid foam to the interior walls. This works well with 70’s style homes that were framed with 2×4’s and insulated with R-13 fiberglass batten insulation.
|‘K’ braces … blown in cellulose nightmare|
Very old homes have no insulation inside the wall cavities or have blown-in cellulose insulation. Blown-in cellulose was typically installed by drilling 2″ holes into the exterior siding, then pumping the feathery, down-like material into holes at the top of each stud bay. Usually one can find evidence of this if there are bunged holes in the siding. Filling an old wall with cellulose only gives a R-value of about 13, which is not sufficient insulation. As condensation forms inside the stud space, the cellulose becomes damp, decreasing its insulative value. Also note the image here, ‘K’ braces in the corners… blown in cellulose will not fill these voids. Only from the inside can one get to these places to insulate properly.
An old home’s insulation level can usually be estimated by the plaster and lathe condition, which was the interior wall surfacing before modern insulation and drywall. If the lath nails are rotted out (see this blog) and the interior plaster, usually new windows, plumbing and electrical infrastructure are also needed. The interior plaster and lathe should be removed, then new studs should be furred out to meet the modern 2×6 wall. I remodeled a home on Gray Street in Portland, Maine where the walls are remodeled as such (read about that here). This is a expensive solution, but is really the best solution because all problems can be fixed at the same time. It makes no sense financially to remodel a home over and over again.
Insulating crawl spaces and basements can offer energy savings. Most old buildings have uninsulated basements; the idea was that used heating system kept the underside of the floor system warm. Some argue and uninsulated basement spaces are acceptable because the earth’s temperature at that depth is warmish and that open walls and flooring makes the plumbing more accessible. However, this thought process was from the days of cheap oil. The earth is a giant heat sink with endless mass. By not insulation your basement or crawlspace, your are essentially attempting heat not only your home, but also the earth. To promote energy savings in your home, the floor system above the basement and should be insulated. If hot water plumbing is hanging down into this space, it also should be insulated.
|Foamed-over brick foundation|
Insulating the basement foundation with either rigid foam or blown foam is important to prevent external ground temperature from bleeding inwards. Keeping this space as warm as possible makes sense, but not by heating it with expensive fuel; allow the insulation to store what heat there is. If your basement has old single pane windows, you can cover them during the winter months with rigid foam board and caulk any obvious drafty cracks.
|The warmth and beauty of stained concrete radiant|
In homes with a decent southern exposure, it is possible to add a radiant floor to increase mass of the building and to promote passive solar heating. This can promote huge savings in heating costs. It is important that a designer with experience in passive-solar design develop the system are floor plan and layout to the south, as well as associated windows on that exposure. It is possible in certain situations to add an external addition on the south side of the building that has a slab on grade with radiant tubing. In some homes, where ceilings are taller than 8 feet, it is possible to install a 1.5″ slab with tubing over the existing sub-floor. This must be evaluated by a designer or builder to ensure that the floor system is sturdy enough and that it doesn’t cause elevation problems in between rooms, door heights and swings, etc.