AirScape Engineer's Blog

We are excited to find that a few utility companies outside of California are now offering rebates for whole house fans. It’s nice to see some forward thinking by these companies. After all, energy savings can come from more than just replacing appliances or installing new windows.

Fort Collins Utility in Colorado is now offering a $250 rebate for the installation of a whole house fan

Pennsylvania is the first East Coast state with utilities offering rebates on whole house fans. PECO and Duquesne Light offer $90 and $130 rebates respectively

If you are a builder in Utah you can receive a $200 rebate on a WHF from Rocky Mountain Power when building a new energy efficient home

The table below lists all of the rebates that we are aware of for whole house fans and solar attic fans (your solar attic fan already qualifies for a 30% federal tax credit). Please refer to the utility rebate website for specific details on qualifications, $$$, and application forms.

We love railroads. Who can’t love their efficiency. BUT… They like coal. They really like coal. According to this report 44% of railroad car traffic is coal. And coal is dirty. It’s dirty in terms of carbon emissions. It’s dirty (but can be cleaned) in terms of particulate emissions. It’s not all that wonderful in terms of mercury dispersal either.

So, which way do you think railroads will lobby (they are corporate “citizens” after all).  Will they throw their weight towards laws which reward efficiency => win for rail transportation. Or will they throw their weight behind more coal burning => still good for railroads.?

You may consider a raised frame for your 1.0 or 1.7 WHF for additional sound reduction. The raised frame increases the distance between the fan and living space. Like our ducted models, making the fan slightly more remote from the living space will decrease the overall sound level. The height of the frame will depend on the total vertical clearance of your attic. The construction is very simple and will add a few additional steps to your installation.

STEP 2:  Caulk all of the frame gaps and joints. Place the provided foam rubber gasket on top of the raised frame.

STEP 3: Secure the unit to the framing (1.7 WHF shown). From the living space caulk all gaps between the unit and the framing.

STEP 4: It’s not a bad idea to add some insulation around the raised frame. You can now follow the remaining steps in the installation and operation manual to finish your install.

PART 1 / PART 2

Your AirScape is already the quietest whole house fan on the market, but there are a few install techniques to make it even quieter. We’ve decided to dedicate a few blog entries to some techniques that will help with sound reduction.

We’ll start with a simple installation step that works with all AirScape models. You can easily line the inside of the framed opening (between the unit and grille) with duct board. Duct board is a resin bonded fiberglass board that has acoustic and insulative properties. The fibrous mat surface of the duct board helps absorb sound and allows for the smooth passage of air. The fiberglass body of this material usually has an insulation value of R-4. The duct board can easily be installed in new or existing installations using either adhesive or screws and flat washers. In fact, we love this material so much we lined one wall of our new office with it (our lead engineer’s rants on energy efficiency, life, and politics are a little more muffled now).

Duct board resources:

http://www.specjm.com/products/ductboard/enviroaire.asp

http://www.owenscorningcommercial.com/data/products/product.aspx?id=271

http://www.certainteed.com/products/insulation/hvac-mechanical/317382

PART 1 / PART 2

Since energy is a topic of conversation in our office, and I have been doing some bicycle commuting, it suddenly became important to have a table of transportation energy use.

Conclusions:

• Bicycle wins the efficiency contest.
• Electric car could win the efficiency contest if you fit 5+ people in your car.
• Escalating that war, the tandem would probably be the next weapon of choice.
• Trains are pretty good (no surprise), and perhaps could get better with regenerative braking.

Assumptions:

• Bicycle uses 50 kcal/mile
• 747 90 mpg (FAA figure is lower,but…)
• Electric car: .25 kwh/mile (from Tesla  if you trust software ‘geniuses’  posing as a car company, or if you trust the old fashioned car company GM, their ‘Volt’ appears to be .34 kW-h/mile)
• <rant> Tesla presents data like a software vendor (no surprise).  Their claim a 70amp @220 volt charger, running for 3.5 hours charges the battery fully (capacity listed as 55kw-h). Energy = efficiency (always less than 1.0) x 70 x 220 x 3.5 = 53.9. Clearly credibility = 1/ efficiency </rant>
• SUV 15 mpg
• Train (swiss) .082kwh/passenger-mile
• Pint of beer has 220 kcal
• kcal (kilocalories) are the kind we eat (aka Calories with a big ‘C’)  Yep, our system of measurement is THAT stupid. Small calories x1000 = Calories =  kilocalories.

Conversion Notes:

• It’s assumed that all liquid fuels have the same energy content as gasoline: 36.6 kwh/ gallon.
• Liquid fuels have crappy energy conversion, unlike electricity which can be 100% efficient.