gas furnace and central AC comparison

[Montreal33]

I have a 1000 sq ft house (plus basement) in Canada, and I need to change a 28 years old nat gas furnace. By the same tolken I wish to add a central AC. I have seen 3 vendors that are offering 2 stage high effieciency furnaces ranging from 60000 BTU to 80000 BTU. They support Kenmore, Carrier and Lennox.

My questions are: which amount of BTU is sufficient? which mark of furnace and AC I should go for (reliability, noise, efficency). Theyare all quite close considering prices.

Thank you

[BaldLoonie]

Somebody needs to do an accurate heat gain/loss calc. My house is 1000 sq ft, I can heat it below zero with 37,000 BTU (low fire of an oversized furnace) so it doesn't take a lot if the house is decently built. I probably should have a 1.5 ton but I have a 2 since I like it ice cold. But then I imagine we get a lot hotter than a Canadian!

If you are looking long term, a 90+ probably makes sense but likely in the smallest size made. Oversized is not efficient and it is noisy, even a quiet furnace. I'd guess anything over a 13 SEER A/C wouldn't pay you back economically.

[Glennhvac]

A/c size will vary greatly by sun exposure too. I have seen small ranch home that may jump from 2 to 3, 31/2 tons just by rotating the home 90 or 180 degrees.
I do not know your degree days but my guess is stay near 13 seer on a/c and two stage may be a big plus on the heat.
As far as Kenmore you may want to see who is installing the unit. In the end that makes or breaks the job.

[SolarMike]

In Montreal, I would seriously look at a heat pump with an electric back up because you have the best electrical rates in the country. It will be cheaper to run and have less service.
8kw or 2.5-3 ton.