Insulating exposed slab perimeter in AZ

[Denwad]

I have a question about insulation. I bought this house in May of this year, its a 1700 sq ft 1 story with vaulted ceilings.

imagine my surprise when my power bill was nearly 500 dollars for July, when at our previous rental house, the worst it got was 300 dollars in July , and this was a 1980 sq ft 2 story.

I know the big hitter in the AC unit, the one at the rental gave up the ghost when we moved in and was replaced by a bottom of the barrel new one.

The AC in our current house was installed when the house was built, in 2004. It seems that it isn't very efficient.

anyway, so an AC replacement is going to be on the plate soon, but in the mean time I thought of something that might help a tiny bit all year round.

The slab of the house is exposed, in most places 6" , and some up to 12". When you stand by a wall you can feel either a WARM floor ( in the summer ) or a COLD floor ( in the winter ). This is true throughout the house

What would be a cost-effective way of stopping this heat loss?

My plan would be to expose the whole slab and spray foam it, plastic sheeting over that and backfill with dirt/rocks.

also the attic only has about 7 inches of insulation ( blown cellulose ) would it be worthwhile to shoot some more around?

I hate vaulted ceilings, crawling around up there is a pain in the ***. Also, who ever the hvac contractor was, cut some corners. The vent going to the walk in closet has almost no air coming out of it, because the HVAC guys just plopped the lineset ontop of it!

wow! and of course its close to the edge of the attic so it'll be real interesting crawling over there and raising the lineset up with some extra wire or something.

 

[ant.foste]

Your first step needs to include a professional inspection with a thermal camera, so you can focus on the biggest heat gain/loss areas. Attic insulation and new quality (no more builder grade junk that's probably already installed) windows and doors will make an enormous difference. From there, an upgraded and properly sized 2 stage heat pump needs to be explored.

 

[PFSard]

Assuming SRP is your provider, this could be worthwhile.

SRP Home Performance with ENERGY STAR checkup for $99
http://www.savewithsrp.com/RD/homecheckup.aspx

 

[mrpizza]

Couple inches of closed cell spray foam would be the ticket for the slab edges. In the attic, blow in 18" of cellulose.

 

[Denwad]

Your first step needs to include a professional inspection with a thermal camera, so you can focus on the biggest heat gain/loss areas. Attic insulation and new quality (no more builder grade junk that's probably already installed) windows and doors will make an enormous difference. From there, an upgraded and properly sized 2 stage heat pump needs to be explored.

can you recommend a decent one?

Will SRP send a quality contractor or a hack?

I mean, I already know i need a ton of insulation in the attic and the sprayfoam won't be that expensive and seems like a nobrainer.

Yes the windows are straight garbage, but will replacing them do that much of a difference vs just putting screens on them?

I bet one of these contractors can answer these questions.

 

[James-W]

Check out the possibility of renting a thermal imaging camera, you may be able to rent one fairly reasonable.

Spray foam is not cheap to have it done but it works extremely well so it is something certainly worth looking into. I would not suggest trying to do it yourself, have it done professionally.

Windows and doors may be something you will want to consider replacing and there may be a tax credit on energy saving stuff for the home. The tax code changes a lot and right now I am not sure if there is a tax credit for energy saving stuff or not.

 

[TractorJeff]

Well?
If you were in Wisconsin right now and wanted to know if the windows were **** that need replacing.
Do what I did!
Get the wife to stand by it when the COLD Wind is blowing!
YEP!
She admitted the windows do indeed need replacing!
Point is a screen will not help a leaky window, only a tinted inert gas filled window that will minimize UV radiation and heat transfer will help in your situation.

 

[ant.foste]

can you recommend a decent one?

Will SRP send a quality contractor or a hack?

I mean, I already know i need a ton of insulation in the attic and the sprayfoam won't be that expensive and seems like a nobrainer.

Yes the windows are straight garbage, but will replacing them do that much of a difference vs just putting screens on them?

I bet one of these contractors can answer these questions.

Can I recommend a decent what?

Windows and doors make a huge difference. The more windows you have, the more heat they're letting into the home in the summer. Sliders and french doors are make for huge losses. You may have R19 in your walls and R30+ in your attic, but those worn out old garbage windows are likely sitting at a R value of <2. Upgrade those windows and doors to a mid-grade new quality unit and be sure the installer insulates between the window and the framing.

I've had neighbors, coworkers, and employees report true proven 30% reductions in their summer electric bills. HVAC is by far the largest portion of your electric bill June-September. Replacing your windows will reduce the running time of your air conditioner(s), resulting in lower electric bills and lengthened equipment life.

Following the windows and doors, a quality 2-stage heat pump installation and duct sealing will round out your energy upgrades with large impacts.

Once the ducts are all inspected and sealed or replaced, then its time to rent the insulation blower thing from Home Depot and load up your attic with more blown in insulation.

Windows
HVAC
Attic insulation

In that order.

Sun blocking window screens will be completely unnecessary with decent new windows, and some windows will actually have their warranties voided by the installation of the sun screens.

 

[850xpeps]

^^^^^^^ this. Good windows, up north triple pane is much better than dual, with plastic spacers not aluminum. Avoid sliders if you can. Spray foam around window and framing once installed. You can blow in the attic insulation anytime and spray foam the slab edges as well. Replacing the Ac would be last step as they don’t draw massive amounts as opposed to furnace or heat loss. And when you get to that point do as recommended and get an ac unit with heat pump capability.

 

[sstec]

Denwad,
I would be concerned about termites with exterior insulation.
I would talk to bug guys before using foam unless they have something to deter bugs. . . .
I spent 15 years down in the SW dealing with them . . . sstec

 

[Denwad]

where would you guys recommend I buy windows from?

I did some additonal digging around in the attic, where my eaves are there is no cellulose insulation just a batt of fiberglass shoved in there

it looks like an alarm company moved a bunch of those batts up there out of the way to run their little wires, and didn't replace them.

of course i can't get down there safely so I'll have to rig some sort of pole to get the batts back

some parts of the attic only have 4" of cellulose

I don't have too many windows , about 10 windows in total, of which 5 are fixed panes, and 2 of those are small ( the one above the door and a small one in the kitchen ). From some of my light reading it looks like it wouldn't be too much of a chore to install windows myself, just not sure which ones are ok to buy. Jen-Weld at home depot or is that just as bad as builder grade?

I have a french door to the back yard, and I just installed a steel security door over it, maybe that'll cut down on the heat gain this upcoming summer?