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  1. #1

    Confused Furnace broken since Thankgiving - the more I research, the more confused I am - help

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    Hi there. We have a 10 year old 2-story house that was originally designed with 2 Kerr oil-fired hot air furnaces and 2 Coleman A/C units. Each set serves one floor. When we had the furnaces serviced this year, the serviceguy found a hole burned through the heat exchanger on the first floor furnace, shut it off, and told us not to use it. He also said that the 2nd floor furnace is showing damage to the metal in the same spot and will probably also be burning through the heat exchanger shortly. The units are not covered under warranty because we are the 2nd owners of the house. We've also been told by two different companies that our A/C compressors are rusting out and not long for the world either.

    So since Thanksgiving, we've been limping along using our 2nd floor furnace and a woodstove, but we're getting sick of being cold. I've been trying to figure out what to do as far as new HVAC goes, and the more I read and talk to people, the more confused I get. So I'm hoping that someone here can provide some unbiased (e.g. not trying to sell me something) feedback.

    We live north of Philadelphia, about halfway between Philly and Allentown. Our house is about 3200 sq ft and for being a relatively new house, is surprisingly drafty - we're working on that now, but it's going to take a while to fix (we're ripping off all the trim and foaming around the windows, doors, baseboards, etc.) Our current system has 2 110K btu furnaces and 2 2.5 ton A/C units. One of the folks I have talked to says that's WAY oversized for our square footage and is probably the reason our furnaces failed so fast. None of the other folks I talked to indicated that the sizing of the furnace was a problem (but then again, no one did an actualy load calculation or any of the other stuff I read about on here).

    We heat primarily with the woodstove, so unless it gets really cold out, the furnaces only come on for a few hours a day (in the middle of the night and early morning when the stove fire has died back). We also run the furnaces when we're going to be away and can't tend the stove and also when the temperature outside is too warm to light the fire (in the 50s, usually). So our decision on what to use for HVAC is complicated by the fact that we mostly run the woodstove anyhow. (And perhaps the fact that we run the furnaces mostly when the temps are warmish makes a good argument for a heat pump anyhow?)

    We do not have natural gas here (we're out in the sticks) and I have no interest in upgrading to propane, so our choices are oil and/or electric. Our electric rates here are very high, and expected to go at least 25% higher once the state deregulates the power in January 2011. We had considered a heat pump, but between the fact that it's too cold here to make a pure electric heat pump economical and the fact that electric rates are probably going to skyrocket, we're not sure how smart that idea is. We currently have an 80-gallon electric hot water heater and I estimate that is costing us anywhere from $80-100 per month by itself. So I'd love to get rid of the electric hot water and convert entirely to oil.

    I have been looking at getting a boiler and indirect-fired hot water system - that would solve the problem of my electric hot water heater being so costly and would also eliminate one of the furnaces - I hate having to pay for 2 furnace cleanings every year, especially when we run the furnaces so little. There have been years where we spent more to clean the furnaces than we spent on oil - that's just wrong, IMO. But the prices we are getting for the boiler are running $xx to xx. We can afford that (though it will be a stretch), but wonder if it will ever pay us back. For that price, we could buy two sets of oil furnaces and probably still have money left over. But then again, we've got the high electric cost for hot water and the extra service fee (~$xx) each year for the 2nd furnace. So I'm left totally confused.

    The other thing we aren't sure about is zone dampers. Currently, we have two separate sets of systems, one for the first floor and one for the second. We are told by some folks that after having this setup, we won't ever be happy with a zone damper system, but other people say the zone dampers work great as long as the installer knows what he is doing. They are pushing it as a way for us to get away a little cheaper by installing just one furnace and a/c system - which I would love to do just to save the service charge every year. But then again, if the zone dampers break every couple years, we'll probably spend as much fixing them as we would on the 2nd cleaning every year. So again, without knowing for sure how reliable they are and how well they work, I can't make a decision.

    Oh, and just to add a bit more confusion, we are hoping to eventually finish our basement and need to figure out what to do for heat down there. If we had the boiler, we could just run some baseboard heat off of it, so that's easy. But if we don't go the boiler route, what then? I can't really tap off the existing ductwork because the furnaces don't run much in the dead of winter due to the woodstove heating the upstairs, so the basement would be too cold. Is my only option then electric baseboard? Or if I do zone dampers, I guess I could make another zone down there. Again - total confusion.

    So anyhow, I guess I'm just looking for some feedback as to what direction to go. Everyone I talk to seems to have some innate bias (one guy was really pushing heat pumps as the way to go, while another guy said he wouldn't consider anything but converting to propane). I'm guessing it will probably be the same here, but maybe there'll be some kind of consensus. So, if this were your house, and you knew you had one broken furnace, one almost-broken furnace, and two A/C units on their last legs (and a 10 year old water heater that could go at any time as well) would you:

    a) install heat pumps (one with zone dampers or two separate)
    b) install heat pumps with oil furnace backups
    c) install a boiler and indirect fired hot water heater
    d) install a warm air frunace (one with zone dampers or two separate) and regular a/c unit?
    or some combination of the above???

    I'm really tired of being cold and confused, so all help is appreciated!

    No equipment, service, or install prices allowed in post.
    Last edited by beenthere; 01-19-2009 at 01:03 PM. Reason: Removed prices

  2. #2
    Join Date
    Jul 2008
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    551
    what are your oil and electric rates?

  3. #3
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,347
    If it were my house (you did ask ) I would do all that I could afford to make the house hold its heat better in winter, and repel heat in summer, with emphasis being on the winter side, being where this house is (PA). You mention the house being drafty, and that you've been foaming around your doors and windows (with a low-expanding foam, one hopes). You may have other issues with your "thermal boundary", meaning how well the insulation was installed, penetrations in the ceiling to the attic (which can allow house air to escape into the attic), and other mistakes in construction that add up to a house not easy to heat or cool.

    Concurrently you have one broken furnace that did not deliver a long life expectancy, and another tracking the same direction. As to why the furnace failed so quickly, since you're the second owner, the prior owners may not have been as diligent with maintenance as you are, with the end result being a failed heat exchanger.

    Back to the "if it were my house" track...I would not go from a two system configuration down to a single zoned system for a two story house. No way, could not talk me into it. Especially since the skill level needed to pull off a good zoned system is in short supply. Multi-story homes are difficult to evenly heat and cool with only one system, even with zoning strategies.

    You would need to weigh the costs of oil vs. propane vs. heat pump with backup electric to gain a comparison of which is the best equipment choice for your area. An energy audit of your home might accomplish this, which also would identify issues with your thermal boundaries.

    Insist on any contractor bidding your furnace replacement options to perform a heat load calculation on your home.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  4. #4
    Join Date
    Feb 2003
    Location
    pittsburgh,pa
    Posts
    727
    Find a contractor to do a Heat loss/ heat gain calc and see what you are lacking. A correct size dual fuel system may be a good option for you. Do not settle for someone just guessing at equipment sizes. " b) install heat pumps with oil furnace backups"

  5. #5

    Confused Furnace broken since Thankgiving - the more I research, the more confused I am - help

    Our electric rates currently hover somewhere around .15/kwh. Interestingly, if we had a heat pump, we'd qualify for the residential heating rate, which makes any winter use over 500kwh/month something like $.06/kwh. If we installed a heat pump, even if we never turned it on, just by qualifying for that rate with our current usage, we'd stand to save something like $80/month. So the heat pump was a no brainer for us (we were going to install outside units with heat pumps) until we learned that as part of the power deregulation in 2011, PECO might be getting rid of that residential heating discount. So much for that. If it's true what they say about rates jumping at least 25%, we're looking at probably not much under $.20/kwh. Yeeouch!

    Oil rates vary daily - we usually prepay and this year our prepay rate was $4.45.gallon. It has since fallen like a rock and is now down around $2.30 or so. Luckily for us, our tanks were full from last year and since one of the furnaces has been broken for months now, we've barely used anything. Whatever we don't use of the prepay gets refunded to us as a credit towards next years oil at the new price, so we should easily be able to get through the winter without using any of the prepay oil at the expensive price.

  6. #6
    Join Date
    Jul 2008
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    551
    Just an FYI. Assume electric rate of $0.20/kWh and an oil rate of $2.50/gal. If you look at a heat pump with a COP of 2.7 around 20 degrees F versus an 82% efficient oil furnace, the heat pump would be cheaper to operate down to around 20 degrees F.

    Considering the prices you are looking at and the uncertain future, i'd buy the highest efficiency heat pump and oil furnace I could afford. If I had to pick one to spend the money on, I'd probably be adamant about getting a 95%+ AFUE oil furnace.

  7. #7
    Join Date
    Aug 2006
    Location
    Chelmsford MA
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    1,518
    Quote Originally Posted by badtlc View Post
    Just an FYI. Assume electric rate of $0.20/kWh and an oil rate of $2.50/gal. If you look at a heat pump with a COP of 2.7 around 20 degrees F versus an 82% efficient oil furnace, the heat pump would be cheaper to operate down to around 20 degrees F.

    Considering the prices you are looking at and the uncertain future, i'd buy the highest efficiency heat pump and oil furnace I could afford. If I had to pick one to spend the money on, I'd probably be adamant about getting a 95%+ AFUE oil furnace.
    Who makes the 95% oil furnace?
    We only want to do it, if we can do it right.

  8. #8
    Join Date
    Jul 2008
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    551
    Quote Originally Posted by nashobasales View Post
    Who makes the 95% oil furnace?
    Here is one:
    http://www.adamsmanufacturing.com/products.html

    There is supposedly 2 more. I'll see if I can find them.

    According to this: http://www.energystar.gov/ia/product..._prod_list.pdf

    Adams
    Domback
    Spartan
    All make 95% oil furnaces.

  9. #9
    Join Date
    Aug 2006
    Location
    Chelmsford MA
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    1,518
    Thanks, didn't know anyone made one already. Wonder how they work with soot build up and such...
    We only want to do it, if we can do it right.

  10. #10
    Join Date
    Jan 2009
    Location
    Keokuk, IA
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    5,520
    I'd factor the wood stove into the load calculations if hte wood seems ot be pretty cheap.

    Sicne the A/C units are ready to be replaced, I'd consider a heat pump along with a matching oil furnace for a dual fuel set-up. Replace the downstairs first, and the upstairs next year to spread out the expenses.

    With the wood stove, it might be more cost effective to get electric supplental heat for the downstairs, and dual fuel for upstairs... assuming electric resistance heat elements are cheaper than getting another oil furnace.

  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,117
    Quote Originally Posted by nashobasales View Post
    Thanks, didn't know anyone made one already. Wonder how they work with soot build up and such...
    They have been out for many years.

    PITA to keep going.

    Can cost a customer more in service/cleanings then they can save on oil.
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  12. #12
    Join Date
    Jun 2008
    Location
    va
    Posts
    800
    My suggestion......Heatpump w/ oil (dual fuel) for main floor, heat pump for 2nd floor.

  13. #13
    Join Date
    Feb 2008
    Location
    Dallas & Longview, TX
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    629
    Quote Originally Posted by machery View Post
    My suggestion......Heatpump w/ oil (dual fuel) for main floor, heat pump for 2nd floor.
    I second that. Make the downstairs a 2 stage compressor sized for the basement also. Go with a variable speed blower.

    I don't think you can lock out the second stage (Pros?) but it would be nice until the basement is finished.

    Run a load calculation with the stove included as mentioned prior.

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