First of all thanks for having this Forum for newbies like me to post, and get advice on HVAC questions.
I live in Metro Vancouver, B.C., Canada and Dual Fuel Heat Pump / Furnaces are starting to gain in popularity here, but most contractors are not 100% up to speed it seems. (Not one I contacted used software to calculate sizes for HVAC residential retrofit applications. I thought this a bit bizarre as I expected more science, and less "rule of thumb", on these expensive integrated systems. They use 800 square feet per ton for heat pump sizing, but then adjust down based on existing Duct work. I have no clue how they size the Furnace )
Our home is 3550 square feet total (2 story + a basement of which 550 square feet is currently unfinished, and used mostly to store stuff we'll never use again => but that's another story!). We had it built 20 years ago from a Jennish Plan, it's 2X6 on 16 inch centers with R26 in the Ceilings. I had an Energy Assessment done a month ago, and the building is still surprisingly good but a little "tight" (0.251 changes per hours versus 0.300). The heat loss for the house is 50,801 BTU's per hour @ 15.8 °F (-9°C) as is =>this reduces to 43,547 BTUs if I insulate the un-insulated portion of the basement foundation walls.
The climate here is quite moderate with the typical yearly minimum temperature of 0.9°C (in December) in my neighborhood, with the extreme minimum being -16°C (3.2 °F recorded on 12/29/1990). There are 39.4 days per years where the temperature dips below freezing (0 °C - 32 °F)
The Yearly maximum is 22.3 °C (August) and absolute maximum 34.5 °C (94.1 °F recorded on May 29, 1983) All data from Canadian National Climate Data and Information Archive. I was away Fishing in the North Pacific, but my wife and youngest son swear it go to 40+ °C last summer in August (104+ °F) for a whole week!
I purchased a Lennox Dual Fuel G61MPV-60C-091 Gas Furnace, a XPG15-042 Heat Pump, and a ComfortSense 5000 Thermostat. (All to replace my original 20 year old Airco Gas Furnace that was still operating nicely.) This system was all installed (along with a Bradford White Hot Water Tank to replace a John Wood unit that worked flawlessly since new 20 years ago as well) last Thursday (2 days ago).
I expected some decent documentation on how to run this as an integrated system, but the manuals for all 3 units don't seem to address this issue. I used to have a programmable thermostat on my old system with typical set back for sleeping and away for work. These are present on the ComfortSense 5000 and I programmed the same old set points.
But I'm wondering if doing so is worthwhile? The Heat Pump seems to be able to keep up a 21°C => 70 °F temperature all day (7°C - 45°F outside) without the G61 kicking in, but when the sleep set back (19.5°C => 67 °F occurs the thermostat turns on the G61 in the morning to bring the house back up to temperature. My brother in law, who lives a few miles away and also has a Heat Pump, keeps his at a constant temperature day and night; and his back up heat (electric in his case) never kicks in.
So is it better to keep a constant temperature 24/7 than use setbacks?
Another question is there any real benefit to having a the circulating Fan in the G61 running on slow speed 24/7? That's the way the installer left it, and said it will elliminate cool spots in the house. We find the noise somewhat distracting.
Thanks for your patience in reading my windy post.
And thanks for the assist.