Seer 13 vs. 14 or 15

askonovdFebruary 10, 2010

We have a new house under construction. The bid includes two 13 seer hvac systems with 5 zones. The brand is Rheem. When we asked about the difference between the different ratings we were told that higher than a 13 costs a lot more money and it would take 15 years to recoup that extra cost. Any advice? Think it's true? TIA, Andrea

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A lot of people think 15 SEER is the way to go. The 13 SEER systems tend not to have too many bells and whistles. A key to all of these systems is proper installation. A lousy installation will kill the SEER rating on any of them. The higher the SEER rating, the more sensitive the unit will be to installation issues.

Higher SEER systems will have more comfort features such as two stage compressors and variable speed blowers. There may not be total economic payback, but your house should be more comfortable for it.

With any system, you need a good installation, including the ductwork. This part of the HVAC system often get short shrift by the installation people. If it isn't done right during construction, you may have to live with a poor performing and uneconomical system for years. Far too many HVAC contractors cut corners in this area in order to get the bid price down and win the job. Make sure the contractor has a sterling reputation and don't let them use flex duct everywhere.

Tell us about your house and include all the specs you have for the proposed systems.

Tiger Dunes is knowledgeable and often posts his minimum preferred systems to questions like yours. I suspect he will be along to do that here.

Rheem is a very good brand. We just installed a Rheem system in our new build.

    Bookmark   February 10, 2010 at 7:30AM
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what is your location?

this is HP or straight AC?

how will you heat?

The Fed Govt mandated 13 SEER as the minimum several years ago. There is no doubt this will be increased probably to 15 SEER in the next several years. You normally get a better condenser with protective devices and improved cabinet when you move up to a higher SEER unit. Of course this usually has to be paired with a var speed blower whether air handler or furnace to achieve the higher efficiencies. The rule of thumb has been a savings of 5% for every point increase in SEER. You definitely want R-410a refrigerant.

Rheem is often an overlooked and underestimated brand. Assuming geothermal is not in your budget range, I would consider moving up to a 15 SEER system. Keep in mind though that builders often use upgrades as a large profit center. The reputable builders/HVAC subs will only go up in price probably their cost difference plus 10%-this would be fair to homeowner and what you should ask for if you pursue this.

Good Luck!

    Bookmark   February 10, 2010 at 9:49AM
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If I were building a new house, I would put strong emphasis on energy improvements (2 x 6 construction, good windows, extra attic insulation, high efficiency heating and cooling). These upgrades in efficiency, when rolled into a 30 year mortgage, don't add much to the monthly mortgage payment, but will pay you back every month in your utility bill.

Energy efficiency in a new house is not as sexy as granite countertops and hardwood floors so it's often overlooked in new construction.

You should also be looking at EER and HSPF (if the condenser is a heat pump) and not just SEER. 14 SEER and higher systems also have higher EERs (Energy Efficiency Ratio) and HSPFs (Heating Seasonal Performance Factor) than 13 SEER builders grade systems.

FYI: 2-stage compressors work well in zoned systems. These are usually found in 16 SEER systems and higher.

Good luck.

    Bookmark   February 10, 2010 at 8:26PM
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From a homeowner here - I put in 2 13 SEER systems with variable speed blowers (got my tax rebate on that one) about 3 years ago. I also have all new doors and windows (good ones but I forget the stats). Gas heat downstairs, also a new high efficiency furnace. Heated and cooled living space about 2800 sq ft. I live in Charlotte, NC. My total gas / electric utility bills for a year are

    Bookmark   February 11, 2010 at 10:06AM
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Here are the must haves on a system in my opinion. First and foremost seal and insulate to the best of your ability/budget as this is the best bang for the buck by far. There are some system options/features that are a must like Demand Defrost, txv, variable speed blower or x-13 motor, and a good outdoor temp sensing thermostat with staged heat strips if it is all electric. The ductwork needs to be sealed with mastic and sized right otherwise seer and all the other specs are pretty much worthless.

If the ductwork is sized right and sealed a builders grade 13 seer with no options can outperform a 16 seer with all the bells and whistles.

I had horrible ducts with gaps I could stick fingers in at connections and returns sucking air out of the attic and basement. I added a return vent and repaired some others that were built wrong and sealed both the returns and supply system and noticed a huge difference with a builders grade 13 seer piston orifice system with a nice honeywell t-stat.

I upgraded to a 15.5 seer Rheem in october with a vision pro iaq t-stat and noticed a big difference in comfort over the builders grade and even though my usage is up over this time last year its not up much and this winter has been horrible in comparison.

I have no regrets replacing my 3yr old 13seer builders grade unit with the Rheem 15.5 seer. I am also now running with 10kw worth of staged heat strips and the old system had 20kw that were staged. I have not had an issue with the house not being able to keep the t-stat satisfied even after dropping 10kw of heat strip capacity.

    Bookmark   February 11, 2010 at 9:18PM
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If the ductwork is sized right and sealed a builders grade 13 seer with no options can outperform a 16 seer with all the bells and whistles.

I assume you meant a poorly installed SEER16 system right?

I must say I like the variable speed blower...especially with the fan set to on all the time. You do not get that constant harsh icy cold air hitting you in the summer or that luke warm heat hitting you all the time in the winter. Sure, at times it ramps up but many times you hardly know its running compared to my prior single stage unit.

    Bookmark   February 12, 2010 at 12:00PM
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OOPs I Meant to say the 13 seer with properly sized and sealed ductwork could out perform a 15-16 seer with leaky and improperly set up and sealed ductwork. Thank you for catching that Andrelaplume. I still would not recommend a 13 seer especially a builders grade if there is any chance to get into a 15-16 seer unit. I was trying to explain what a huge impact the ductwork can have on a system.

I totally apologize for any confusion.

    Bookmark   February 12, 2010 at 7:29PM
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Thanks everybody for the great info. We will meet with the HVAC guy next week and I will have lots of questions for him. I especially like the variable speed fan. I guess I should have said that we will be heating with propane & the a/c is just electric. Our water heaters will also be propane powered. I will be happy to report back when we make a final decision. Thanks again to so many helpful people here on Gardenweb. Cheers! Andrea

    Bookmark   February 12, 2010 at 10:48PM
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Propane is one of the most expensive heating fuels.

Depending on your electric rate, and your climate, your operating costs may be cheaper with a high-efficiency heat pump as primary heat, and a propane furnace as auxiliary heat to the heat pump.

    Bookmark   February 13, 2010 at 8:01PM
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With Goodman for example, you need the 14-SEER to get the TXV & Copeland Scroll compressor; which I consider essential.

Of course, you could have them install a coil with a TXV with the 13-SEER condenser.

The duct system & airflow are absolutely critical to efficient economical performance. Problem is it usually takes a 15-SEER to get some rebates.

Here is a link that might be useful: System Sizing & Duct Sizing

    Bookmark   February 17, 2010 at 9:15PM
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garyg, yes propane is expensive but so are our electric rates. We had a heat pump system about 10 years ago in a different house. I was always cold. There is just something about electric heat that feels cold to me. I am just probably weird! Our last house was heated with propane and maybe because it was so well insulated we did not get super high heating costs. I hope we find this true in this house. I think the zones help with that. We found them very helpful in the last house. Thanks again for the tips. Andrea

    Bookmark   February 18, 2010 at 11:37PM
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Heat pumps have improved immensely in the last 10 years.

But still, they only produce heating temps in the mid 90's and not the 140's of a gas furnace. And the heat output of a heat pump drops with ambient temps.

What is your delivered price of electricity (in cents per kw-hr)? Delivered price = generation + transmission + distribution.

What is your cost of propane ($ per gallon)?

    Bookmark   February 20, 2010 at 8:43PM
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