Looking for feedback from experts, optimists, and naysayers.

Is the extra cost of spray insulation worth it for a new construction build?

Will the electric bill be greatly reduced?

Do you install a smaller AC because the house is near "air tight"?

Would it be safer to go with normal batts of insulation?

suggest trying the home improvement board

I can answer you right here.

I keep my A/C at 76 during day when we're at work, 72-74 when we're home, and 70 at night. This is also "no humidity" so it is pretty cool.

The wife and other women who are over literally dress for my house, with long clothes. There are blankets available for those who need them and are often used.

My electric bill is around 135 per month (June - Sept); about 100 April/May and October, and maybe 75 bucks or less in the winter.

Compare that to those in CS with utility bills of 300 - 400 dollars - I figure I am making 100 - 200 dollars back per month compared to average in town utility costs.

So if spray foam costs 8000 more, I will make back my investment in 6-8 years or so (making more back on investment May - Oct than winter months)

Also its quieter in the house. Almost no noise from cars outside etc.

So to sum up, I highly recommend spray foam.



[This message has been edited by SARATOGA (edited 7/17/2012 8:37a).]

I can't tell you the exact returns on foam as to savings on electric bills. Foam does allow you to downsize the HVAC a bit so that your system doesn't short cycle, not removing all of the humidity in the house. I believe I pay around $1.40/sf for foam in the walls (2x4) and $1.00/sf for foam in the rafters (6" of foam). Both of those are heated sf vs surface sf.

A more cost effective option that will give a much better insulative value (R as well as air infiltration) is to do a wet blown cellulose or Spider (fiberglass). They are blown in place in the wall cavity with a glue substance that dries with the product and it stays in place until the drywall is installed. This method fills gaps and holes and around electrical boxes much better than a fiberglass batt would.

The attic can then be done with lose fill Spider or you could have foam sprayed in the attic, either open cell in the rafters, or closed cell in the ceiling joist bays. The rafter version makes your attic a more conditioned space, but may require some fresh air intakes for HVAC if you have gas heat, or gas water heaters if located in the attic.

An insulation contractor could give you the run down of the two options and pros and cons of each. Your HVAC contractor should be able to run calculations for you on a chosen SEER rated system, between the two systems called for tonnage wise, depending on the insulation chosen, to give you an idea of energy savings between the two systems. I would stay away from the batts though. Hope that helps and doesn't just give you info you already know.



[This message has been edited by toolshed (edited 7/17/2012 8:50a).]

Saratoga, how big and how old is your house ?


When you say $135 is that your total bill for water, sewer etc or just for electrical only ?

originaltexan,

Feel free to give me a call and we can discuss our products with you and answer any questions. I run Brazos Valley Spray Foam and I always welcome the opportunity to educate about foam
systems.
Jacob- 979.587.1606

Texas A&M Class of '05

Jacob,
Don't have time right now to call, but please post your comments. You would help a lot of mybcs'ers.

Ooshwa:

" Spider in the exterior walls and Spray foam in the attic and underneath"

Was Spider cheaper than foam?

Why didn't you do ALL Spider or ALL spray foam?

Did you buy a smaller AC unit than the recommended size for your sq footage?

Thanks. Your comments are appreciated.

Who was your builder, ooshwa? Like the sound of those things!!

The straight box idea is smart. I've seen 6" and 8" flex duct collapse because it is run 25 ft.

Thanks for your comments.

I bought a house (albeit in Humble), but it came with spray foam.

My attic areas have not gotten above 95F. I keep the AC at 77 at night, 85 during the day (we aren't home) and 80 when we get back.

I used ~800 kWh for the month of June and currently have used 450 kWh for July (I have a device that measures the power usage as well).

House is 2 story 2600 sq. ft. I have a 4 ton unit (single).

I think my last electric bill was $85-$90.

Overall, I have like R-40 something in the attic and R-20 something in the walls.

~egon

originaltexan,

There is a lot that I could go over concerning spray foam...and could send you article after article about it's benefits. Long story short, spray foam houses are the tightest most efficient houses around. As posted, spider also makes a competitive insulation product. Here is a website I strongly suggest you visit and consider using if you are still in the planning stages of your home. There is a lot of good information there. And again, if time is available, feel free to call us to schedule a visit.

http://www.energywisestructures.com/

-Jacob
www.brazosvalleysprayfoam.com

I'm not an expert and am probably getting the jargon wrong.

I have open cell spray foam in the rafters and the walls including the garage. My house is over 3700 sqft. with 12 foot ceilings in the common areas and 10-11 foot ceilings in other rooms including bedrooms. The front of the house faces north. The house has little to no shade from trees even though I do have trees in my backyard... they're just too far to help.

I have a single 5 ton 16 SEER two stage AC unit and a heat pump. I had an engineering firm (Energy Wise?) size everything up (including ducts) and they included a guarantee that my HVAC system would never consume more than $100 of electricity a month and the spray foamer says they typically overshoot so I should see much less than that ($60-70). However, I would be required to install a separate meter to measure how much electricity it was consuming (which I never did). Oh yeah, I have 6 returns! One in each bedroom and 2 in the common areas. Everything is setup into 3 zones.

I keep my house at 76 and I'd say it's comfortable. My daughter's room we keep at 73. At my last house, we'd have to keep the house at 74 and it would be running constantly during the summer. I think you can set the thermostat 2-3 degrees warmer with spray foam.

I can confirm that the attic is more than tolerable even when it's 100+ outside. I can also confirm that the garage, while hot mid afternoon, is no where near as hot as my last house. In my experience spray foam does not help dampen sound that much. Or maybe my vinyl windows suck. I have Alenco windows and I hear they're not that great.

I set my thermostat to 78 during the day Tu-F when no one is home. I have to stagger the zones to cool down the house for when we get back home. Otherwise, it'll run nonstop trying to cool the house back down to 76. I've had the HVAC people over several times trying to adjust the ducts. Before I figured out I needed to stagger the zones, the temperature would be stuck at 78-80 for several hours throughout the house. I tried setting the thermostat to 80 during the day but it took too long to cool the house back down. When I first moved into the house, it seemed like it only took 5 minutes for the temperature to drop 1 degree.

My spray foam guy claims that they did spray foam the garage ceiling (he definitely did the rafters over the garage). I'm not convinced and just haven't gotten around to verify it for myself. The pull down ladder to the attic in the garage has absolutely no insulation. The garage doors are not insulated and are always closed.

Last year, I had one electricity bill that was almost $400. That's just electricity. We do not have a pool, only run laundry once a week, and have 2 fridges (one that's 12 years old and the other less than 2 years old). We rarely use the dishwasher. My wife prefers hand washing since we're only a family of 3 and don't accumulate that many dirty dishes. We have MR16 halogen recessed lights throughout the house.

This was a new construction so I don't know what it would be like without spray foam. Here's my power consumption:

Billing Periods Number of Days Daily Usage Total Usage

06/2012 33 60.15 1,985.00
05/2012 29 44.72 1,297.00
04/2012 29 38.55 1,118.00
03/2012 30 27.73 832.00
02/2012 31 29.97 929.00
01/2012 32 29.09 931.00
12/2011 31 36.65 1,136.00
11/2011 29 31.66 918.00
10/2011 29 46.59 1,351.00
09/2011 30 68.27 2,048.00
08/2011 34 93.65 3,184.00
07/2011 29 82.83 2,402.00
06/2011 32 77.03 2,465.00
05/2011 30 46.63 1,399.00
04/2011 29 34.55 1,002.00
03/2011 32 25.84 827.00
02/2011 28 33.07 926.00
01/2011 34 38.35 1,304.00
12/2010 30 34.60 1,038.00
11/2010 29 38.41 1,114.00
10/2010 28 51.61 1,445.00
09/2010 27 69.30 1,871.00

I haven't raised a big stink (yet) because I figured it was just so hot last year. But something doesn't seem right. Either the spray foam company was full of it, or they didn't foam my garage ceiling, or the HVAC guys didn't follow the engineering spec to the letter. Probably a combination of all 3. I seem to recall the spray foam guy being surprised that the HVAC people setup my house with 3 zones.

I'm still unsure it was all worthwhile. I'm just not getting the results I was expecting (peaking at $200, not $400!) I did call CS Utilities last year for an energy audit and was told by them that my house was doing very well. But they didn't come by the house, they just used the rule of thumb of expecting (I think) $.10/sqft and I was well under that at the time.



[This message has been edited by CN (edited 7/19/2012 10:52a).]

Energywise looks interesting.

I emailed them to check their cost to tell me what size of AC I will need.

We have foam in the attic and spider in the walls. Last week when it was rainy and cooler outside, I had to go into the attic for something and it was almost chilly (!) in there! We have a 5 ton unit, I think 16 SEER, 2800 sf and no shade coverage. My total utility (elec, water, sewer, garbage) bill was over $400 once last year and just this month went to $400. I can't say if it saves us a lot, but I DO know that our house is very comfy at 76, A/C shuts off regularly even on hot days, and if I bump it to 75, I need a blanket when sitting on the couch.

I've owned a spray foam business for 4 years. I don't spray in the B/CS area. PM and we can talk.
Ron '76

Was considering adding it to an existing home. One HVAC guy mentioned that there is some potential issue with mold associated with houses that are so tightly sealed with the foam insulation.

Is that a legitimate issue? If so, is it easily avoided somehow?

agfan, that was our builder's concern as well. We're building a house right now and opted for the spider insulation. One reason, we plan on being in this house 8-12 years and weren't sure if we'd recoup the cost of the foam insulation. The other reason was the concern for mold in the humid climate.

Your HVAC guy should be able to install a fresh air exchange to get fresh air into a tight house in a regulated amount. Also, I he sizes the unit correctly to run long enough to get the moisture out of the air it shouldn't be an issue. The contractor has to do his load calculations right to keep the unit from short cycling. It can be done properly though and you can have a foam insulated house with no mold.

Again, not an expert.

No issues with mold here but our house is less than 2 years old. My understanding is that you need a 2 stage unit (only available on 16 SEER units on up when I built my house) to prevent mold. A buddy also has spray foam throughout and he hasn't had any issues with mold (his house is a couple of years older).

Also, I was hoping to replace all my thermostats with Nest learning thermostats but they're not compatible with 2 stage AC.

Thanks for the replies!

quote:

---

I need a blanket when sitting on the couch.

---

If you need a blanket at 75, you have circulation problems.

Nope, no circulation problems. 75 in my house might feel cooler or less humid than someone else's.