Thursday, January 31, 2008

And the winner of HVAC efficiency is...

...Us! We did a manual J calculation of our SIP (Structural Insulated Panel) home and found out that our house was very efficient at 941 sf per ton! The average HVAC contractor normally sizes HVAC units at 450-550 sf per ton.

What does the ton mean? Your HVAC (Heating Ventilation Air Conditioning) system is sized by the ton. Typical sizes for single family residences are between two and five tons. Each ton equals 12,000 Btuh. Basically, it means our house is so air tight, insulated and efficient, it would take a 3-ton HVAC unit to cool our SIP house compared to a 5-ton HVAC unit to cool a stick built house that is the same size as our SIP home.

Our future house, a 2419 sf home, is the most energy efficient home that our green architect has ever designed. :-) Sorry to toot our own horn, but it makes us a bit proud to know this.

6 comments:

Clinton @ The Barter House said...

Jan & Myleen,

I think it's awesome that your project is the most efficient design your architect has done to date...

I'm not using SIPs, but I hope between CMUs and SPI (spray foam insulation) I'll be able to toot too!

Clinton
Barter House
LiveModern Reader

Jan & Myleen said...

Thanks Clinton! I would be very curious to know what your HVAC will be sized at. Please feel free to post. I saw your house and you're so lucky that you're almost done :-), congrats!

scott28411 said...

Really great blog. A very descriptive and helpful diary for both aspiring homebuilders and professionals alike.

I'm an architect in NC, and we had a similar experience with a slab & SIPS house in coastal NC. Our Manual J calcs came in with a rec. load around 2.5 Tons for a 2,400 SF house with a passive-solar sunspace and good orientation & shading (plus our cooling loads probably aren't as bad as yours). The recommendation to the client was to upsize to 3 ton- mostly for humidification control, but it's going to be an extremely efficient house! However, you never know when a hurricane may blow by and take out some of your Western shade.

Looks like a great house....
Good luck with construction!

All the best-
Scott from Wilmington.

Jan & Myleen said...

Thanks Scott! That's valuable info, and I think we're right around the same calculation. Keep the comments coming, as I enjoy hearing from other architects & professionals.

RAJESH B KUKREJA said...

Really great blog. A very descriptive and helpful diary for both aspiring homebuilders and professionals alike.

I'm an architect in NC, and we had a similar experience with a slab & SIPS house in coastal NC. Our Manual J calcs came in with a rec. load around 2.5 Tons for a 2,400 SF house with a passive-solar sunspace and good orientation & shading (plus our cooling loads probably aren't as bad as yours). The recommendation to the client was to upsize to 3 ton- mostly for humidification control, but it's going to be an extremely efficient house! However, you never know when a hurricane may blow by and take out some of your Western shade.

Looks like a great house....
Good luck with construction!

All the best-

Jan & Myleen said...

Thanks Rajesh! Your J calc sounds similar to ours and it's fantastic to hear that you're building green. I am hoping by making this site, people will see how it goes (the good, the bad, and the ugly)... thanks for coming by and keep bringing in your valuable input.