New home build. Upgrade A/C or Insulation?

[hal1]

I'm on a budget, and $550 really might make a small difference to me.

I'm buying a new, to be built, house in Phoenix. I couldn't tell you much about the construction, it's a basic big builder house. 1734 sq ft. Gas heat.

They are offering an A/C upgrade from 14 SEER to 16 SEER for $545.00, and Insulation upgrade from R30 to 38 for about $550.00 too.

According to the electric company here, it's estimated that my summer electric bill will be $150, so about $100 of that will be to run the A/C.

Will either of these pay for themselves in 5 years?
I heard that over 102 degrees the A/C will not see such energy savings from 14 to 16 SEER.

I suppose if I finance both of those, over 15 years, that that may cover the additional $7.00 cost in my mortgage.

 

[zmaxmotorsports]

Id go with the insulation myself.

 

[Ohmthis]

Insulation, you can always upgrade the ac later.........Not the insulation.

 

[hal1]

Insulation, you can always upgrade the ac later.........Not the insulation.

Would I see similar cost savings?

 

[Bookworm]

Read the paper, watch the news. U.S. national policy is such that electricity rates are skyrocketing, by design.
Just read an article a few days ago, power rates in my region are going to rise by almost 20% in the next few years, to cover the cost of regulations already announced. No telling what is up the sleeve of the agency in charge.
Upgrade the insulation. Payback will be shorter than you can calculate with the current rates. The insulation will keep paying off for the life of the building. The a/c unit will need replacing in 10 years.

 

[CNGsaves]

I'd do both. You'll never get chance for those 2 again in 20 years.
Payback likely quicker than normal in harsh heat of Phoenix.

Also make sure your attic has proper Ventilation.

Tell wifey NO SHOES for the next year and give up fast food for 6 mths !!

 

[larry4406]

Look at your permit. 2012 IRC Code I think would mandate R38 in your area. Thus charging you to "upgrade" to be code compliant seems like fraud to me.

 

[nadogail]

AC can be upgraded or supplemented whenever. Insulation is difficult and costly (in my opinion) to upgrade later.

 

[shade]

$150 in the summer for a 1700 sq ft home - guess again....

 

[pablo94sc]

I'd go for the most insulation you can get and supplement cooling with fans if needed. Double check the insulation level after a couple months and settling has occurred to make sure you got what you paid for.

 

[Mike-]

Insulation, you can always upgrade the ac later.........Not the insulation.

I don't agree at all.... Opposite!
You can always add a few batts to your attic later!
But upgrade you ac in a couple years will cost you 3000$ at least!
Do both if you can, if not do ac.
Check into code as Larry said!

 

[DC73]

Insulation, you can always upgrade the ac later.........Not the insulation.

AC can be upgraded or supplemented whenever. Insulation is difficult and costly (in my opinion) to upgrade later.

The builder isn't talking about wall insulation. He's talking about taking R30 attic insulation to R38. It would require either an extremely thick wall to get to R38 with conventional insulation or a 2x6 wall full of very expensive closed cell spray foam.

Attic insulation is cheap and easy to add later but my opinion is that you need both R38 and 16 Seer in Phoenix. Both will pay for themselves eventually - not sure about 5 years but the electric company could have some thoughts on this. I'd ask for their recommendation. Sometimes power companies offer rebates for installing higher seer units.

You could have the builder do the AC upgrade and then do the insulation yourself. But first, go to Lowe's and/or Home Depot and price insulation. It could be the builder's incremental cost of going from R30 to R38 is a good deal.

You have a couple of options for adding insulation yourself later. You could put additional batts on top of what the builder puts down. Or you could blow in cellulose or fiberglass. Both Lowe's and HD will loan you a blower machine with sufficient quantities of purchased insulation.

If you absolutely have to pick one over the other, I'd opt for more insulation.

If you plan to be in the house long term, it makes sense to do both.

DC

 

[bzinsky]

Can you spend it on better windows instead? Or window treatments like blinds/shades?

Please keep in mind insulation attic will do little to save on cooling cost, just heating.

Give an estimate and say 10% of your exterior walls are windows, and estimate an r-value of 1.5 for those windows.

If I had to put $550 to upgrade my homes efficiency, I'd probably use it to upgrade the window treatments to blackout cellular shades on tracks. I'd think that'd be the best bang for the buck as you could double or triple the R value of a significant portion of your exterior wall vs a slight increase in your attic or AC compressor. The extra window insulation will reduce heating and cooling cost, where as the options you are giving only reduces the cost of one or the other.

Looks pretty good as a bonus.

 

[7echo]

Are they required to do a Manual J calc? If so, what do the numbers say vs what the contractor is installing?

 

[nadogail]

Shade wrote "$150 in the summer for a 1700 sq ft home - guess again.... "

My year-round average Gas & Electric bill was $350 to heat and cool a 2400 Sq Ft house in Coronado, CA. After my solar system was installed, my year round electric bill is $125 per month, locked in for 20 years, last months gas bill was $15.

My cash outlay for my solar system, 26 panels, was $3000.00.

The solar company is responsible for all the system maintenance, for the next 20 years.

I figure that in 14 months I will have made back my $3000.

PM me and I will put you in touch with them so you too can slash your electric bill.

 

[larry4406]

Look at your permit. 2012 IRC Code I think would mandate R38 in your area. Thus charging you to "upgrade" to be code compliant seems like fraud to me.

Seriously - Look into your permit and see what version of the IRC Code your AHJ is using. Should be as simple as calling the inspections office with the address/lot number. Here in VA/MD we are using the 2012 IRC Code and it REQUIRES R38 minimum in the attic and R19 in the walls.

 

[bzinsky]

Shade wrote "$150 in the summer for a 1700 sq ft home - guess again.... "

My year-round average Gas & Electric bill was $350 to heat and cool a 2400 Sq Ft house in Coronado, CA. After my solar system was installed, my year round electric bill is $125 per month, locked in for 20 years, last months gas bill was $15.

My cash outlay for my solar system, 26 panels, was $3000.00.

The solar company is responsible for all the system maintenance, for the next 20 years.

I figure that in 14 months I will have made back my $3000.

PM me and I will put you in touch with them so you too can slash your electric bill.

I'm 2750sq ft and it costs me about $150/month on average to heat and cool, nothing special done to the house other than being relatively new and well sealed.

 

[Showkey]

^^^^^^^ little saving on cooling ?????

Using the calculator R30 to R38 upgrade for $550 is a 11.2 % return on investment.
Many will argue the best solution would be R48 to R60 but the return on investment drops to 5% depending on the cost of upgrading. Minumum 5% return guaranteed over 20 years....not too bad......11% no brainer. Stated Return caculation is if power cost remain flat which is not likely.

Phoenix cooling degree days is 6722, heating 200.

With the chuck wright calculator you can change the cooling unit efficiency to get a direct comparison between insulation and equipment payback. If you do both upgrades they do off set saving slightly.


Maybe use one of the many calculators to get exact saving:

http://chuck-wright.com/calculators/insulpb.html

Get the degrees days from:

Weatherdatadepot.com

http://www.degreedays.net

 

[hal1]

thank you everyone for all the helpful information. It seems I really can't go wrong with either of them.but leaning towards installation only at this point. The increase to 16 seer may not net me much on a brand new house

 

[kj_mustang]

2009 code for Phoenix is R-30 for ceiling
2012 code for Phoenix is R-38 for ceiling
Depends on which code the government authority is requiring builders to use.

 

[hand]

In general, I would advise paying the builder only for those upgrades which are difficult to do in the future. Most production builders make money on upgrades - it is unlikely they are priced lower than your cost later with a third party or DIY cost unless it is something that requires significant rework.

For your specific question - I would recommend spending the $550 on a pre-drywall inspection by a third party... Ensuring you are actually getting the insulation / air sealing / other behind the walls components you are paying for is likely more valuable than any alternatives.

 

[DC73]

^^^^^^^ little saving on cooling ?????

Using the calculator R30 to R38 upgrade for $550 is a 11.2 % return on investment.

Can you list all of the inputs you put into the calculator to get the 11.2% return? I couldn't even get close. Note that the 2nd column for r-value is not the final value, it is the "added" value so the 1st column gets 30, the second gets 8.

The only way I could get to 11% plus ROI is to input over 30 cents per kWh for electricity costs.

DC

 

[zmaxmotorsports]

Can you spend it on better windows instead? Or window treatments like blinds/shades?

Please keep in mind insulation attic will do little to save on cooling cost, just heating.

Give an estimate and say 10% of your exterior walls are windows, and estimate an r-value of 1.5 for those windows.

If I had to put $550 to upgrade my homes efficiency, I'd probably use it to upgrade the window treatments to blackout cellular shades on tracks. I'd think that'd be the best bang for the buck as you could double or triple the R value of a significant portion of your exterior wall vs a slight increase in your attic or AC compressor. The extra window insulation will reduce heating and cooling cost, where as the options you are giving only reduces the cost of one or the other.

Looks pretty good as a bonus.

I always wondered who it was that used words like "window treatments",Now we all know!

 

[zmaxmotorsports]

I dont want to make my head explode trying to figure out all this return on investment stuff.
I look at it in simple terms.The tighter and well insulated a house/barn/garage or dog house is,The more of the conditioned air that is going to stay inside of it.
And the better it can hold that temp,the less the heating/cooling system is going to have to run to maintain that temp.

 

[larry4406]

2009 code for Phoenix is R-30 for ceiling
2012 code for Phoenix is R-38 for ceiling
Depends on which code the government authority is requiring builders to use.

Exactly. So a simple phone call might reveal that the structure is permitted to 2012, which would mean R38 would be required. Many jurisdictions do not perform insulation inspections, so a builder could put anything in and get away with it.

 

[CNGsaves]

^ ^ ^ There you go. Tell builder you'll pay the $550 extra but that will be for double dose of insulation above & beyond R38 to R50 since the R38 should have been included anyway. Never can have too much insulation, especially in severe climate like Phoenix.

 

[Showkey]

Can you list all of the inputs you put into the calculator to get the 11.2% return? I couldn't even get close. Note that the 2nd column for r-value is not the final value, it is the "added" value so the 1st column gets 30, the second gets 8.

The only way I could get to 11% plus ROI is to input over 30 cents per kWh for electricity costs.

DC

I screwed up

You are correct 11% is NOT right..........I used the wrong number in the second column. 4-5% is the more correct value depending on the inputs. The only way to get to 11% or greater is lower costs and or greater R value by DIY solution.

 

[TangoFoxTrot]

I could see either of them probably taking around 5 years to break even. I don't think either are big game changers, you'd probably save more money on your cooling bill just adding some extra ceiling fans if you don't already have them or what was mentioned earlier with window treatments.

 

[truckman5000]

check your local utillity company/ state for rebates on insulation. Here you can get an existing home over insulated. With 75% off cost upfront. Im going to do my home through the program, 700$ for the entire home 3k sq ft.
Here it dosnt matter if its new, as long as you own the home.