On the surface, this is a no brainer: newer houses that are built with the latest and greatest building materials, insulation, and appliances.
But here’s the true hidden factor: the residents or homeowners of the house ultimately influence the amount of energy that is used. An energy savvy homeowner in an older house has a better chance at lower energy bills than the homeowner in a newer house who is careless and mistakenly thinks that simply having a newer house will lower energy bills by itself.
That said, what could possibly be in a new house that could potentially cause it to be less efficient than a home 20 years older?
First there’s the possibility of an improperly sized HVAC system. HVAC (Heating, Ventilation, and Air Conditioning) contractors are trained to size and install a heating a cooling system at least equal to the needs of the house. The contractor inspects the home, makes his calculations, and orders the supplies. A cost is drawn up, and work begins. The ductwork is put in, the appliances installed and tested.
Much of the time, the contractors are completely correct in their sizing of the system. After all, they are professionals. However, if there is an addition, or if there is more to the house added after the HVAC system is installed, the system may now be undersized. What does an undersized HVAC system mean? If it has to condition a larger area at the same efficiency, the unit will run longer and thus use more energy.
Another gaffe can be placing the HVAC registers near windows and doors. This is especially prevalent in split level homes or newer homes with large bay or front facing windows. Often times there is no other place to put the register, so it goes in front of the window. As long as the window is new and covered (and insulated well) most of the time this shouldn’t be a problem. But down the road, as the window insulation fails, this can be a major source of energy loss.
Another offender is placing registers too close to sliding glass doors that lead to a patio or outdoors. Often times, these doors are added after HVAC installation. The effects are obvious – when the doors are opened energy is forced out of the house at a very fast rate.
Newer homes also tend to have more exhaust fans than older homes. Exhaust fans are not like other standard fans that simply circulate air. Exhaust fans actively force or remove air from a space. In this case, that space is your home. They are essential in attics to prevent ice and pressure buildup, but exhaust fans in range hoods and lavatories (as well as in some dens, especially those with fireplaces) pose an energy risk.
Newer homes also pose a greater risk for insulation gaps. Insulation gaps, or insulation voids, are areas of the wall (most commonly) where insulation settles or is simply not installed. This may be done on purpose or accidentally. An example of “on purpose” insulation voids can be found around most recessed lighting fixtures. The reason is because these fixtures are not properly insulated units, so fiberglass insulation cannot come in contact with the unit. So, as much as a square foot or more of missing insulation will probably be present around such units. Many ceiling fan junction boxes have the same requirement. Insulation here, though, may be just “missed” because the walls are often a primary focus. Sometimes the installer may also miss insulation in a wall, especially near windows or doors or switches/outlets. This is because often times the insulation is not done at the same time the electrical work is done.
If the new house has an air conditioner, the placement of the air conditioner unit is important as well. Although most are insulated, if left out in the sun, it may have to work harder. HVAC contractors sometimes take this into account, and sometimes are tied to a location based on the location of the HVAC ducts. Luckily, you can counteract this by building a small open enclosure to protect the a/c unit.
Keep in mind when you are thinking about a brand new home that there is simply no history of energy bills for the house. So in effect you are flying blind. You can make educated guesses based on the energy star stickers, the area temperature, and your appliances (assuming insulation is to spec) but there is no real way to accurately predict future bills.
Also, many newer housing developments where homes are built are noticeably void of trees and other taller vegetation. Older, taller mature trees are cut down to make way for the homes, and in their place (sometimes) there are a couple of small, younger trees. Trees provide a natural wind break and provide shade. In the winter, when deciduous trees shed their leaves, they let sun through while still providing moderate wind protection. This is an effect 95% of people forget about when looking at the majesty of a brand new home.
Ultimately, here is the bottom line. Under most circumstances, newer homes have an immediate energy efficiency advantage over older homes. Ultimately it is the residents of the home that at least partially control the home’s energy usage. Still, newer homes may have energy problems older homes may not have that you should be aware of. And we outlined those above.
David Anderson continues to be so completely obsessed with home energy and finding ways to reduce energy bills that he’s now losing sleep over it. He is a regular contributor to the Utility Bill Busters Blog, a site updated (almost) daily with a ton of free tips and resourced for helping homeowners save money on their energy bills. It can be found at http://www.utilitybillbusters.com. (And if you want to know more about insulation voids and how to conduct your own energy audit, check out http://www.energyaudits.net!)