I am not sure your numbers are correct, 3 ton = 36,000 BTU, so producing 45,000 seems unlikely. Also as it gets colder the capacity of a heat pump goes down, due to a reduced temperature differential. Most heat pumps are name-plate rated at 45 deg F.
paul
My numbers are not incorrect. 36,000 BTU is at 50 - 60 hertz and that's what the unit is rated for. Some units "specialize" in heating capacity that can operated down to -15 degrees and still give you 90% rated capacity. These unit run even a higher heating capacity at 17 degrees and yet even higher at 47 degree (outside air temp). Part of the problem is online retailers in general have no clue what they're selling and sell what peopel want, and forget the end user asking questions at a box store LOL
Just like cooling for example (as far as ratings and capacity). One manufacturer, two different models. Model A is rated down to 24 degrees. Model B is rated down to 14 degrees. Model A cost 70% more than model B. Guess who everyone buys? Model B of course. The issue is people don't look at the submittal information and understand that with some optional ad on's (yet more money), model A will operate down to 0 degrees. People still say "so what, it still costs way too much". I understand that. But also understand that with model B, looking at the performance chart, at 24 degrees outside air temp, a 2 ton AC unit may only give you 12,000 BTU's of cooling because of the capacity loss. Model A on the other hand, on a two ton unit, will give you 24,000 BTU's of cooling at 5 degree outside air temp. For most residential applications, no one really cares. However, when you're dealing with a IT server room or a room where cooling is critical year round, the capacity loss on a cheaper unit at lower temps can kill you and your equipment (all temps are fahrenheit of course here) .
In general, heating is actually the primary concern when it comes to mini splits and residential applications (but people don't think about that until afte the fact when the unit can't keep up with the heating demand when it's 20 degrees outside), and cooling can be the primary concern (if there is one) when it comes to commercial applications (cooling year round, even when it gets cold outside).
Part of the issue is training, the other issue cost. Contractors and homeowners want to jump on the bandwagon because they hear so many great things about mini splits, but when it comes to buying time, if someone can buy a 22 SEER system for less money than a 20 SEER system, it seems like a no brainer to buy the 22 SEER system.
Keep in mind, with so many different lines being sold, the issue becomes IMO that the cheaper the unit you buy, the greater the odds that in 5 years you won't be able to find any parts for it if you need one. That said, I still remember in 1999 waiting 4 months for a compressor for a mini split unit literally coming from a slow boat from Japan. Then it had to hit California, then ship east. With Korean and Chinese lines? I wouldn't touch them with a 10' pole lol (thing is, back in 99, you didn't have Korean or Chniese lines being sold in America).
Please at least stick to buying Japanese (that said, ironically enough, units manufacturered in Japan, but some parts are made in Korea, go figure LOL).
