When I started this blog, my intention was to provide information about various ways and products to improve the sustainability, energy efficiency and or healthiness of your home. As an ASHI home inspector for the past 10 years, I have seen countless “improvements” or “upgrades…some with the best of intentions, and some, well let’s just say misdirected! Sometimes the results are good but sometimes things go horribly bad.
As part of the economic stimulus plan, the federal government is offering tax credits for a wide range of energy-efficient products, from windows and doors to solar water heaters. This can be a great program helping people to improve their homes. However, these increases in efficiency if not planned with the “whole house” in mind, could lead to some serious “unintended consequences”. As we start to increase the efficiency of homes, building science comes more and more into play as we must take into consideration what negative effects may be brought on.
One of the most common improvements is to upgrade or replace the heating and air conditioning system. This used to be a relatively straight forward job. You just replaced the existing system with an equivalent system. These days, with the very high efficiency systems and different options available like variable speed fans, there really needs to be new calculations done to determine exactly what size is needed. If other energy improvements have been made to the house such as additional insulation or high efficiency windows and doors, it’s even more important.
For example: Say that the existing system in a home was installed in the mid “90’s and is perhaps a 3 ton system and the SEER (Seasonal Energy Efficiency Rating) rating might be 10. Now with a little encouragement from the government and a desire to decrease energy bills, the home is upgraded to a new 14 or 15 SEER system with perhaps a variable speed fan. If it is replaced with a similar sized 3 ton system, the home could develop humidity and mold related issues as it may be oversized. When all these factors are not taken into consideration, you end up with at best a poorly performing system but at worst what a colleage calls “a science project” in your home. Excessive humidity, mold, poor indoor air quality and increased rather than decreased energy consumption could result.
This is just one example dealing with heating and air conditioning, but there are often “unintended consequences” from any high efficiency upgrade. Just remember that changing one system in the home often affects another. Does this mean that you should shy away from improvements for fear of related problems? Of course not, but keep in mind these things:
- Do your homework on the improvement you are planning. Is it the best for your money? Are there known downsides?
- Hire a reputable contractor who is knowledgeable about and willing to discuss the interactions of the systems in the home.
- Never accept the explanation “that’s the way we always do it”. The times they are a changin!
