Hello -

Our energy company is offering a full-blown energy audit, completed with a blower-door and infrared imaging for $120.  We are trying to improve the efficiency of our new (but very old) house so I want to take advantage of this.

Right now it's pretty hot in Denver and we don't have AC. So, the difference in temperature between the inside and the outside isn't always much. In the winter, it's incredibly cold out and nice and warm inside.  Do the thermal imaging systems need a substantial difference in temperature to get good data, or should it be ok if we do it now?

I was thinking it might be best to wait until winter to do the audit, but maybe the equipment is much more sophisticated than I realize!

any advice appreciated! thanks, Dave

I've been told that winter is better. You can compare IR pictures with the blower door pushing and then pulling - which makes even very small leaks stand out.

I think in your location and situation it would be better to do the energy audit in winter.  By the way, energy audits can cost a lot more than the price you have been quoted.

Thanks for your replies. Alton, what kind of expenses might occur? Maybe I can be best prepared for the audit and make the most of it while keeping additional costs down!

Thermal imaging is really cool "high tech" and all, but fixing all the obvious air leaks, following up with a blower door test to find the less-obvious leaks is usually more useful in an old house, since air-leakage is likely to be a bigger and more readily fixable heat loss than conducted thermal losses through the walls, etc.

But you can do very reasonable thermal imaging in Denver in hot weather if you keep the windows & shades closed in the morning, and conduct the test during the high temp part of the day. The surfaces that get direct sun will appear hotter, than those that don't, but if the studs image out cooler than center cavity it's and indication of low or absent insulation, etc. Anybody who uses thermal imaging cameras can interpret the results. It'll be a bit more obvious in Denver during the heating season, but not dramatically so. It's tough to tell anything if it's 74F inside and only 76F outside, but if it's 90F outside, 78F it'll be pretty obvious.

Insulation contractors who do air-sealing as a service will usually do blower-door tests before & after as proof that they've actually reduced the infiltration rates by a prescribed amount. If it's obvious that your place need more insulation & air sealing, finding an air sealing contractor and just doing the job is money better spend than confirming the obvious with a kewl gadget like an infra-red camera. (A $75 pistol-grip infra-red thermometer from an orange or blue box store can tell you about as much as a camera, but it takes more time.)

But a $120 price tag is a bargain (it's probably subsidized), if they're competent. It can take a few technician hours to do the necessary testing & write-up. Most independents in my neighborhood are charging north of $500 for blower-door+ thermal imaging testing on a residential sized building, but some local utilities have been known to offer those services gratis over the past few years (but not MY gas provider.)

The service is subsidized, yes. The rep from the power company told me that they normally go for $500+ but some legislation from the Obama administration is subsidizing this service. So, I think I gotta go for it!

We used a blower door and thermal imaging camera yesterday. As Dana says the blower door is the primary instrument, but where air was infiltrating it showed up on the infared which will detect differences as low as .1oF.