Installing natural gas furnace (Carrier Infinity 96) and humidifier (Aprilaire 600) - with motor running all the time

Hi,
I am replacing natural gas furnace and humidifier for my house. I got estimate for this from local company. What I am wandering about is that this furnace has variable speed motor that runs all the time. Because humidifier usually works the same time as motor is running, it means that my humidifier will run all the time. Q: Are there on the market special humidifiers that are specifically designed to work with such furnaces?
P.S. I contacted aprilaire and they told me that their humidifier will work in such setup, just I have to use hot water for humidifier. But I am not sure at this point if this would be efficient setup.
Thanks
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First did you know that Infinity is only 96.7% on the 38000 btu model, All the rest the larger sizes are apx 94.5%. Im not cutting them down as I am getting one instaled also. But every salesman I had out lied. The fan doesnt need to run 24x 7 , that is you option. A humidifier only adds water when it is needed and does not run continuosly April air also has a humidifier with a set and forget model, it has an exterior thermometer as well. This is the best way as you wont overhumidify or under, you set it to where condensation occurs on your glass then just back it off. You dont need hot water unless your house is real big and leaky, try cold first. Look into the new thermostat they carry you can adjust everything from it, even fan speed and humidity. Be sure they do a load calc
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Ransley,
Thanks for pointing these things out. Thermostats that let you adjust everything (fan speed) cost about 300-400$ - not that cheap. Strangely my sales rep did not calculated btu I need for our house. We have 3500 sq feet house + finished basement about 1000 sq.feet. Estimate I got was on 100,000 BTU. My current furnace was 120,000 BTU. I live in Toronto, Canada, so winters here are preaty cold. Not sure why sales rep recommended 100,000 BUT - I will have to ask. I found on internet, that approx calculation should be : sq. feet x 35.
Thanks

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I know what you mean. I am in process of getting a new furnace, I am in Ottawa. All the contractors I has so far estimated anywhere from 80-110 input MBU furnaces. My house is 2300 + 1100 basement. When I did my own heat load calculations, I have calculated 98,000 BTU. Makes me wonder. They have been in the business long enough, but that does not meen too much. They seem to come up with a number after you give them the magic number of square footage. Few of them do calculations, few of the would go though trouble of checking insulations etc. they spend 30 min doiung the estimate, so you can't expect too much. Using generic values is fine, but a simple rotation of house can make a difference. And when you tell them that you have done load calculation they look at you like you came from mars. I took one electrical course in local college last year, the ppl that were taking it, some of them wanted to be apprantices of electricians, could not even add few numbers in their heads. Colegue of mine bought a new house, huis furnace was undersized by about 15000btu. It took over 30min to raise the temperature of the house by 1C. This house was built by big company. After going on for few months having problems with dealing with them, he involved city inspectors and all got fixed in a month. The company could not even produced a load calculation for a sample contruction of the same house type. So, I am not saying all of them are bad, but be aware. Also, if you are looing for a good thermostat, check out honeywell on ebay. A you can save a bundle.
martin

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Martin,
Did you find that price for the same equipment is much different between contracts? So far I have just estimate from Direct Energy and awaiting calls from other 2 contractors, but I am still not sure if price difference is more that a few hundred dolars. What I read is that installation is as important as furnace brand, so I am planning to go with big and reliable company, of course if it is not going to cost more than 200-300$ dollars. How did you calculated heat load for your house? I do not want to buy bigger furnace than I need, but from what you are saying most likely I'll need at least 120,000 BTU, as my house is a bit bigger than the one in your example, and you get 98,000BTU. Of course windows, walls, etc. impact that...
Thanks
"Martin" <none> wrote in message

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How well does your 120000 heat at the coldest point in winter and how is its recovery if you set it back. Remember your old furnace may be 50-80 % efficient so a new 94.5% efficient 100000 btu furnace may put out allot more heat than your 120000 of 80 %. I dought your old is 80 % but if it is thats 96000 btu output. A new 100000 94.5% is outputting 94500 btu. Your old unit is probbly much less than 80 % in output efficiency so you are lilely fine.
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OK,
Now as we started to talk about BTU... My current furnace takes about an hour to raise 1 degree in the house. So it is really to small. I checked, and I have 120,000BTU input furnace at 60% eficiency. that makes about 72000BTU out. Strangly, on the furnace it says max BTU out is 91800. So maybe eficiency of my furnace is higher? So now if I will get 100,000BTU in furnace at 94% eficiency, that means I will have about 94000BTU out. That is much better, but I am not sure if it is enough. So, anyone know how much price different would be between 100,000 BTU furnace and 120,000 BTU furnace? Also, if I want to change variable fan speed from my thermostat - do I have to request installers to add extra wire from furnace to thermostat or all wiring is same as for old furnace?
Thanks,

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1 degree an hr. geese , thats bad, loose your heat for a day and you will have trouble recovering, I do 7 per hr. with a 2 stage, which is ok because I go out of town and set back all the time.
Did they do a load calc in writing ? Demand one. Do you have good insulation ? look.
At 1 degree an hr you are spending a fortune running the blower almost continously.
You Need more BTU so you have recovery and dont run 24x7. But you dont want it oversized either or you get hot fast. Sizing is critical for comfort.
New wiring will need to be run im guessing, but fishing with existing wire is easy.
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