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  1. #1
    Join Date
    Mar 2010
    Posts
    7

    Heat Pump vs Heat Strip System - TX

    I currently reside in an all-electric TH in Houston, Texas area and I am in the process of getting quotes for a replacement system. My old 20 yr + Lennox 3 ton Heat Strip / AC system has died. Should I go with a Heat pump or Heat strip for the heating side - I'm worried a bit about electric rates down the road as natural Gas rises and electricity goes up in cost. Looking for guidance in replacing this system. I see a lot about HP on this and other forums.. not much on Heat Strips. Thanks

  2. #2
    Join Date
    Sep 2002
    Location
    I don't know
    Posts
    2,909
    What are your "winter" bills like?

    Climate?

    Heatpumps in all but the warmest climates (temp never drops below 45F) require heat strips to temper the air during defrost cycles and provide backup below the balance point. (balance point is temp below which the heatpump can't keep up without supplemental heat) The air handler and heat strips will most likely need to be replaced anyway, so the real question is whether the extra premium for a heatpump (over a standard a/c) is worth paying. Modern heatpumps can reduce heating costs by 2/3s over heat strips alone in mild weather - above 32F. It must also be noted that they put out cooler air in heating mode than heat strips.
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  3. #3
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,752
    I always learn stuff at this site!!! Wondered how defrost was handled for heat pump only systems! Thanks amd.

    The incremental cost of a heat pump very quickly justifies itself on energy savings alone. You can expect 3-4x the increment back over the life of the unit. That doesn't begin to factor other benefits.

    As is so often true when you cheap out... You will regret not making the investment for a long time, if you regret making it the regret will be short (in this case you won't regret making it).

    If you have Natural Gas get dual fuel/hybrid heat. Currently somewhere between 15f and 25f is the economic balance point depending upon gas and electric in your area. Below those temps a 95% eff gas furnace will provide BTU's cheaper than a high efficiency heat pump.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,566
    Quote Originally Posted by amd View Post


    Per unit of energy, gas is far cheaper than electricity from power plants - presumably you don't have natural gas available.
    Its not the unit of energy that counts as much as how you use that unit. of energy.

    At 10 cents a KWH and 1 dollar a therm for gas.

    A HP at a COP of 2.8 is cheaper then a 95% furnace.
    If its a 80% furnace, then its a COP of 2.4.

    At outdoor temps of 40 to 30°. Aux heat during defrost is more for comfort.
    Generally temps below 30 if aux heat doesn't come on during defrost, the HP won't be able to recover the temp lost during defrost. Before the next defrost cycle begins.

    Being in Houston, his A/C requirements should be enough that his thermal balance point is quite low. May not even need aux heat. And he should save considerably with a HP over straight electric strip heat.
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  5. #5
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by amd View Post
    It must also be noted that they put out luke warm to cool air.
    your were not very specific about this cool air

    when does a heat pump put out cool air while in the heat mode

    how cool is this cool air you are speaking of?

    usually in the cooling mode you will get 60 degree supply air

    but your saying a heat pump delivers cool air during the heating cycle?

    i know what you meant, but maybe the guy contemplating a heat pump doesn't



    .

  6. #6
    Join Date
    Jul 2005
    Location
    FLORIDA
    Posts
    1,163
    here we go again

    a heat pump is only going to recover the added cost in the heat cycle

    xxxx.xx for a heat pump and only 30 days a year heating to recover the cost
    will take 20 years to recover the money(maybe) and one repair on that cadilac and you never get it back

    for weather in the 40's to 50's this thing is a beast but as you get lower temps it starts to be useless hit the 20's in FLA and and the heat calls went crazy here no heat ho heat

    houston looks like its right on the cusp for a heat pump like northern fla
    if you have weather like atlanta you will save big if its like tampa may never see it again
    once you think you've seen it all
    (THINK AGAIN)
    I would rather work for free than be look upon as a thief!!!!!

  7. #7
    Join Date
    Sep 2002
    Location
    Northeast Ohio
    Posts
    4,854
    While the cost of the new system will most likely be middle to upper $ XXXX.xx the actual added EXTRA cost of a heat pump over straight AC system is more like upper $ XXX.xx. In his particular climate, why wouldn't he go the heat pump route?
    A good HVAC tech knows how, an educated HVAC tech knows why!

    DEM


  8. #8
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,327
    Would you people please read a post before you reply, the OP stated they live in an all electric Townhome so no, gas is not available.

    Heat Pumps are an excellent choice for Houston but it can take a considerable time to payback the extra cost. As stated by others it depends on what your current electric bills are.

    If you go the HP route it is best in fact imperative that you install a variable speed blower if not you will have humidity control issues during the summer. You will also need to upgrade our return air capacity as you are most assuredly undersized even for a straight A/C system.

    There are other options that can drastically reduce your electric bills on an all electric TH besides the HVAC system.

  9. #9
    Join Date
    May 2006
    Location
    Arlington, TX
    Posts
    107
    Hi CB57... As others have stated, it's all about your current costs for heat, which implies asking, how much do you use it? If your townhome is a "middle" unit and thus sandwiched above and between other units, you would have very little exposure to the elements and thus probably use very little heat, in which case paying extra for a HP model probably makes no sense. It's all about the LCCA aka life cycle cost analysis. Most smart "clients", be it residential, commercial, etc, will insist on a LCCA to justify the added cost for any type of more efficient system.

    If your townhome has a lot of exterior walls and roof, HP may be the way to go. Let us know what your heat usage is like, and we can be much more helpful. Thx.

  10. #10
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    Quote Originally Posted by dirtyboy103us View Post
    for weather in the 40's to 50's this thing is a beast but as you get lower temps it starts to be useless hit the 20's in FLA and and the heat calls went crazy here no heat ho heat
    My 3-ton, 14 SEER / 9 HSPF heat pump can maintain a 68F indoor setpoint at 25F ambient without the use of aux electric strips.

    At 25F ambient, the pump puts out 91 degree air (based on a 70F return air temp).

    The palm of your hand is about 89F, so any moving air close to that temp may feel cool to the touch.

    Take care.

  11. #11
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,281
    we have had the coldest winter in years in this area
    I've been doing some diagnostic work for a local utility
    company, for their high utility bill complaints.
    all houses are straight a/c with electric strip.
    While I can identify where the house problems are
    their best investment would be to change to a heat
    pump when work on house is done. Usually once
    the house if fixed (air and duct leakage reduced) current
    hvac is oversized, thus a good time to change unit.

    one client paid almost three times in Feb (and 3x kwh usage)
    than in August. with heat pumps winter time utility costs are
    much lower. for our climate heat pump upgrade cost pays
    for itself in less than 3 years.
    electric strip is the most expensive way to heat.

    best of luck
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  12. #12
    Join Date
    Mar 2010
    Posts
    7
    Thank you all for the replies:

    Some additional background - The reason the HP has been brought up during replacement is that I annually serviced the units I have, and the serviceman commented several times over the years that when the units were to be replaced he would replace w HP w backup strips rather than plain Heat strips, My TH is Electric only – NO gas… The electric bills this winter (Usually 2 months) was about $180/mo while running about $80 in the summer. I also do not inhabit the main room in the winter very much where this unit would manage since I keep the T Stat at low-mid 60’s for cost purposes. It is expensive to heat and keep this big room compfortable and warm in the winter. I have systematically worked to tighten the envelope of this TH with double pane windows, weather-stripping, caulk etc. so I am cognizant of energy conservation methods and the monetary ramifications.. I see energy costs going up in the future and being all electric, I am sitting at a crossroads in a choice of units.

    The main livingspace in this TH that this unit manages has lots of windows and faces NW w 1 big main room w loft , 20 x 40 w 26ft arched ceiling running the full length. Some of the windows are double paned Low E Argon - except the 2 large 6 ft Ό circle windows that are 19 ft in the air which are single pane. These will be upgraded when I get the $$. Recent Man J (HVAC-CALC) states that 2.5T Min - is needed. The old unit in the attic is 3T.

    If strips or HP are the way to go (either way), I have some configurations I have been quoted and would like feedback on the equipment combinations (no pricing) to insure an efficient and good workhorse unit is installed. I'd like to get the Tax Credit if that can be managed w/o tradeoff in upfront cost. Have some Bryant and Amana units quoted. I would also like guidance as I have been reading about this subject (in this and other forums) for a while over the past several months since I knew I had to deal with this expense in the Spring. The businesses I have contacted seem to be BBB members with good track records and seem to know what they are talking about.. I'm spoiled as this old unit lasted 20+ years. I have a second unit that might need attention in a few more years, but right now its working fine..Thank you in advance..

  13. #13
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,618
    If you have $180 in the winter and $80 in the summer. You are going to fall somewhere in between those 2 numbers when you have a heat pump installed. The heat pump won't run as much in the winter as the a/c does in the winter. It is Texas afterall, it gets lots hotter for longer than it does colder. But you are still going to be running the heat strips off and on for supplemental heat. The system will run probably 10 years before a coil leaks or a compressor fries. Figure in the price of a heat pump vs. heat strips installation vs. 10 years of survival. I think you'll probably break even if not ahead by installing a hp, unless your contractor has a huge price difference between the 2. Which I wouldn't expect them to be.
    I like DIY'ers. They pay better to fix.

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