I’m sorry, but your general statements are incorrect. Heat pumps are indicated for much of the US and are very popular in Canada as well.
You can purchase 100K BTU units in the range I described. In any case, that’s getting large. My entire home uses 35,000 BTU
http://www.trane.com/residential/en/resources/hvac-basics/is-a-heat-pump-right-for-my-home.html is from the Trane website, and they say that a heat pump is not effective below 25-30 degrees, which is not an uncommon temperature, and people in colder climates who have them usually have an auxiliary heat system when it gets too cold. I don’t know where you get that heat pumps are indicated in much of the US, in the northern tier of the US, or in the midwest, temperatures in winter are routinely colder than that, even for highs, and in Canada even worse. Not to mention that as efficient as heat pumps are, they are electric and in many places electricity is much, much higher cost than gas. It is why heat pumps are not common in the northern tier of the country, they tend to be used in milder climates that see the 40’s or so as a low.
http://www.askthebuilder.com/heat-pumps-how-well-do-they-work/ states that below 37 degrees, a heat pump cannot keep up.
As far as 35k working, that depends on where you live, with a typical house of roughly 2000 square feed, you would be talking a 100k input, in bigger houses above that, in the northern tier of the country.
There are heat pumps that operate far below zero. Trane is not the leader in heat pump technology.
I live on the northern border, and my home is many times that size.
I guess it’s true that you can’t believe everything you can Googleup.
BTW, you can’t size your heat requirements based on square footage.
Heat requirements are proportional to the square feet, since the heat load is a function of the volume being heated, which is square footagexceiling height, other factors are the temperature differential from outside air to required temp (usually 68F is used), plus the insulation level in the house is obviously a factor, a well sealed home will require less heat input. Given that ceiling height is usually relatively standard throughout the house, then one of the biggest factors in the heat calculation is going to be the square footage, if typical houses have 10 foot ceilings, and have let’s say the same insulation level, then square footage is going to be the greatest difference in the btu needed, a 2000 square foot house would require significantly less than a 3000 square foot house.
Been busy with the Google?
Okay, so far we have
You’d have to explain how, if all those factors vary, heat loss is proportional to “the square feet”.
very easy, I was careful to say in my post that assuming that items 2-5 are the same, that the heat required is going to be proportional to the square feet. If you take two houses that are built to the same standards, let’s say built to code, then a 2000 square foot house has less heated volume then a 3000 square foot house, and thus the 3000 would take a proportionally larger heat source to heat it, square feet would be the major factor. Obviously, an airtight, well insulated, 3000 square foot house that takes advantage of passive solar could take less heat than a 2000 square foot house with crappy windows, little insulation and so forth, there is no doubt, but if we are talking houses with the same kind of insulation and sealing and more than likely ceiling heights, the square footage would be a dominant factor.
We have two heaters, each a little over 100K BTU. Looking over old records, I see that one of the heat exchangers has been replaced 10 years ago, both blow motors 7 years, circuit board multiple times. The way the two heaters were connected stumped many techs. Whenever they couldn’t figure out what’s wrong, they ordered new parts. If the furnace is made of a heat exchanger, a citcuit board, and a blow motor, I may have a newer heater than I thought and would make sense to just replace the cracked heat exchanger. I’ll be talking to two more contractors tomorrow. I’ll see what they have to say.
Heat exchangers are a couple hundred bucks and a fair price for labor might be about $800, so a thousand total. You can roughly calculate the payback time on a new, more efficient unit by comparing the efficiencies and applying the difference to your estimated heating cost.
And then, there’s the possibility that the old unit may need additional repairs soon.
I got 4 bids. All except one said our heater is too powerful for the house and would do fine with 140,000 BTUs instead of 220,000. The new price is around $6-7K instead of 16K. With that price, I think getting a new furnace makes more sense. I narrowed it down to a Trane or a Carrier. Which is better?
@iglooo:
I have a train unit that is now about 10 years old, a high efficiency model, and it has worked perfectly since it was installed, been very happy with it. About all we ever do with it is get it checked yearly by the gas company (basic maintenance under the contract), haven’t had anything go wrong with it through some pretty cold winters.
Trane it is then!
Amazing what some shopping around can do?! Good luck with the replacement.
Do you have any thoughts on chimney liners? Our old terra cotta chimney liner is no longer up to standard. The contractor is looking into a model that will do away with a chimney liner. Is it as effective? I read it up and it looks like the liners do good at taking exhaust out of the house.
My chimney has a liner (due to the chimney having structural problems) - my hot water heater vents through it as did my former gas home heating system. When I replaced the heating system and got a new high efficiency unit - it vents instead through a small PVC pipe which goes directly outside through my outside concrete wall. The heating unit (and hot water unit for that matter) have to match the type of ventilation you have (so a unit that needs a chimney or liner will not work with a different type of venting).
I can’t vent to the side of the house. That’s why we are getting 80% efficiency unfortunately. I’d like to do my share to protect the environment and use a high efficiency but it’s not to be.