how much furnace do I need?
Results 1 to 6 of 6
  1. #1
    Join Date
    Jan 2012
    Posts
    1

    how much furnace do I need?

    3 days after I moved into my new townhouse in BC (early Dec) my furnace broke. It took quite awhile to notice because the house stayed quite warm. It was the noise that alerted me. I had it looked at, apparently I need a new furnace. Estimated cost for 95% efficient around $$$$. My issue is, I have been 6 weeks without a furnace, lots of cold days (0 to -14)and one oil heater plugged in on each floor (two) is sufficient except on the coldest days (gas fireplace for a few hours picks up the slack). The house is actually sometimes too warm. Do I really need a 95% furnace. I may only live here 2-3 years, so I'd rather not spend more money than I need to and clearly this house doesn't need much to stay warm!

    Naturally, HVAC people I've talked to all encourage the $$$$ expense, yet I see new 80% furnaces for sale at under $$$$. I would be most appreciative of some honest advice.
    Last edited by jpsmith1cm; 01-26-2012 at 06:09 AM. Reason: Removed pricing

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,884
    In a townhouse with a smaller heat loss than a house, an 80% furnace may be the wiser move. Sounds like it won't take a very big one either. Make sure any dealer quoting runs a heat loss calculation (aka Manual J) and sizes right.

  3. #3
    Join Date
    Dec 2004
    Location
    Derby City
    Posts
    3,958
    The key for me in making recommendations is the amount of time you anticipate remaining in the home. It is important to be aware also that with virtually all (if not all) residential equipment providers, the additional warranty available on higher end furnaces is ONLY to the original purchaser and not transferable to a subsequent owner. If you do go with a furnace with the extended warranty be sure to SEE IN WRITING that the warranty is in fact transferable.

    With that being said, I agree that given your specific circumstances, an 80% furnace would be the more economical purchase and provide you with satisfactory utility bills and comfort. I concur also that whoever you choose, should have calculated a manual J heat loss load in order to PROPERLY size the new unit.

    Irish
    Everyone has a purpose in life..........even if it's to be a bad example.

    Seek first to understand, before seeking to be understood.

  4. #4
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,829
    Your question is, "How much furnace do I need?" The answer is, as little as possible. Now the only real way to determine that is by a Manual 'J' load calculation performed by a trained person. Once the size of the furnace is know and the duct system has been checked for proper sizing, then you can discuss the various model options. This is the only acceptable method of determining the size of furnace you need. It sounds like it should be quite small in Btu's per hour and since they only make furnaces in specific sizes, it may turn out you'll get much better comfort with one of the pricier models that's either a 2-stage or modulating furnace. Furnaces are rated as to their maximum input in Btu's and the 2-stage and modulating, while having a maximum rating/capacity will have a lower minimum capacity than a single stage that has but one. Thus if your needs fall substantially below those of the smallest furnace, you'd benefit by having a smaller input on 1st stage or lowest modulating per cent than the maximum rating on the furnace. Your company of choice should be able to thoroughly brief you on those issues if they're germane to your needs.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  5. #5
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,846
    IMO, a very important efficiency tool for either furnace choice, is a programmable room thermostat that has a swing or cycles per-hour setting.

    Many close temp-tolerance RM-stats will short cycle the on/off heating cycles, which is not as an efficient use of energy.

    These RM-stats allow you to set the temperature variation for the temp-variation you're comfortable with, and to get the off-time & on runtime cycle lengths you want.

    If you dress warm you won't notice the temp-variation & the set point can be lower, saving on energy costs.

    Your contractor can show you what they have to offer you; or, Ace Hardware has the ACE ATX 1500 with the 1 to 9 swing setting at a very affordable cost.

  6. #6
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,595
    What ever you buy, make sure that you get a "variable-speed" blower.

    I would be interested to know if they have mentioned that?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event