These are heat pumps...

Are the new heat pump the same size as the old ones? What thermostats do you have? Do you know if it has a cool to dehumidify feature?

Same size...both 1.5 ton units. Honeywell thermostats, cannot find numbers but are basic units, has demand defrost control, do not know about cool to dehumidify...

Obvously there is no standard reason for what you are experiencing so it requires testing to find answers. Are you experienced with a vom,amp meter and electric calculations. Understanding the basics of refrigeration will also be helpful. If so tell us and we will go foward from there,if not,you need the installer to come back and check it out.

You can't compare season to season.

You need a humidity gauge then take ðF temps of closest supply air register & return air; @ around 50% RH temp drop should be around 18 to 20ðF.

Outdoor condenser discharge air temp around 14 to 15ðF temp-rise over outdoor temp. Post Results!

Do a load-calc on the different floor levels. You have to print the results when U think it is RIGHT, as can't save results.

Here is a link that might be useful: Free on-line Load-Calc

"I replaced my 9 YO, 10 SEER Goodman units (upstairs and downstairs) with 15-SEER Ruud units late last year. In going over my electric usage for the summer, my usage gas increased by 5-7% in a summer with many less 90 degree days. I was figuring 15-20% savings...not this!..any ideas? I live near the coast in S. Carolina..."
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Well, that doesn't sound too good; living on the coast in South Carolina the humidity level is fairly high your 2.5% summer design is 92 Fahrenheit dry bulb 78 Fahrenheit wet-bulb a -14ð drop which gives you a high 54% relative humidity outdoors. At 92ðF that's a lot of grains of moisture per pound of air.

If the relative humidity was a lot higher this summer than last summer, then that could equate to using more electricity; however; do the tests that I indicated in my last post and we'll see what we come up with, the humidity we need is the indoor humidity because that determines the Fahrenheit temperature drop indoors in the Fahrenheit temperature rise outdoors off the condenser.

The condenser discharge air has both the sensible & the latent heat load Incorporated within it, therefore, it is a good indicator of how much each is being transferring to the outdoors.

It also may indicate whether you are drawing hot humid air from the attic or garage or some other source in the return air; the duct system should be checked for air leaks and for proper insulation on any ductwork that is not within the conditioned area.

I would like to know how you use gas in the summer. Ruud is not as energy efficient as it could be. It sounds like you need to have the thermostat checked and it uses e-l-e-c-t-r-i-c-i-t-y in the summer. Not gas.

Those 10 seer units were very efficient when it came to high humidity conditions, they had larger compressor's with greater volumetric efficiency at pumping down the evaporator's pressure and temperature resulting in a colder coil and better humidity condensation performance.

I would have advised him to keep the 10 seer units as long as possible, especially in his climate. However, it could be that they're not performing properly; in addition, we need the indoor temperature along with the humidity percentage and all the other temperatures that I requested to provide a ballpark estimate as to how well your heat pump units are removing heat from your home.

I believe he was so upset over his election electricity rates going up and he said gas instead of electricity, I will totally overlook that mistake as I feel compassion for the poor guy who spent considerable money with the belief that he was going to get 15 to 20% savings on his electric bills.

Those SEER estimates are conducted under laboratory conditions and can seldom be repeated in the field; IMO, equipment should not be sold on those estimates.

udarrel wrote " Those SEER estimates are conducted under laboratory conditions and can seldom be repeated in the field; IMO, equipment should not be sold on those estimates."
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Yea,kinda like those water saving toilets forced on consumers. I actually know people who installed them eventhough they didn't need new toilets because they wanted to do the right thing and help conserve our water supply.
EPA estimated fuel consumption #s are something you should trust when car shopping.LOL

Post Mdl numbers of both outside condenser and inside air handler. Date of new install? Even if it was just a 13 SEER HP system, I wouldn't expect electric usage to be more. I would want to know that the charge is correct and within manufacturer specs. I assume you have ruled out any other non HVAC reason for increased electric usage.

Post back.

IMO

I believe the OP's typo is gas = has.

Correction:
In going over my electric usage for the summer, my usage has increased by 5-7% in a summer with many less 90 degree days.

could one of the electric heat elements be activating by mistake during AC operation?

Model numbers--
Ruud -----15 PJL18401---2 units

A/H--Ruud----RHLL-HM2417JA-- 2 units(closet and attic, same as old units).

3705625 Active Systems RUUD 15PJL SERIES RUUD AIR CONDITIONING DIVISION 15PJL18 RHLL-HM2417+RCSL-H*2417 600 18500 12.50 15.00 17700 8.50 10800 1 HRCU-A-CB Yes 149 456 Yes

Nice systems and they qualify for Fed Tax credit.

The only thing I can suggest is that the air handler and condenser are pulling the correct amount of power and are within mfg spec.

Also the suggestion that the heat strip s not operating when in AC mode.

Since this is electrical in nature, dealer tech should perform this work.

Have you discussed this issue with installing dealer?

IMO

Some easy simple ways for anyone to check the performance of their air-conditioning system

Try to check the run time and off times of the air-conditioning system and write down the outdoor temperature; it's best to do this on the hottest days and even when the humidity is at its highest.

Let's say the air conditioner runs for 15 minutes, then off for 15 minutes before it restarts, that's a total of 30 minutes for complete cycle so you take 15 minutes and divided by 30 minutes and you get .5 or 50% runtime; will say I have 2 ton air conditioner but due to ductwork and other factors that will not deliver even 23,000 BTU per hour instead figure 90% of 23,000 and multiply that figure 20700-Btuh by .5 that is only 10,350-Btu used per hour.

That formula can be used for any complete time span cycle. Another formula is the EER or energy efficiency ratio formula; the BTU per hour divided by the wattage used. Another way to use the formula is to take the BTU/hr and divided by the units EER rating.

Let's say the air conditioner as a nominal rating of 23,000 BTU per hour divided by a 9.5 EER that is 2,421 Watts of power used. A technician can then taken amp probe and multiply the amps times the checked voltage which will equal Watts the unit is actually drawing. From that reading you can figure what its actual EER is.

Another way to verify what the load is, is to do a load Calc; I'll provide you with the free online load Calc with which you can experiment with until you get a proper load Calc performed, which you will then have to print out because you cannot save your load Calc's.

You can also use a indoor humidity gauge and write down the humidity level while taking the temperature difference between the supply air in the return air in your home; then go outside and take the temperature of the discharge air and subtract the outdoor temperature from it.On a 10 and 12 seer condenser the indoor split at 50% relative humidity and 80ðF will should be around 19 to 22ðF. The outdoor condenser split should also be between 19 and 22ðF.

Totally Free Load-Calc
This Free online calc will help you determine equipment sizing & point-out areas that need efficiency retro-work - Once you calculate the page it saves the inputs for up to 24 minutes or, until you change inputs or close your browser.
You can easily reduce infiltration rates yourself, therefore, IâÂÂd use 0.4 ACH (Air Changes per Hour) be sure to add the (Air Changes per Hour) CFM into the âÂÂFresh Air Recommended âÂÂline-slot, or it wonâÂÂt figure the Infiltration & fresh air Btuh.

Print & read all the load-calc instructions; when U think U have it RIGHT Print the results; U can't save the results...

Here is a link that might be useful: Free Whole House Load-Calc