Replies

1. Expert Member
   Dana Dorsett | Mar 15, 2013 05:36pm | #1

   Your average mid-winter lows are a more important consideration than the outside design temp for making this choice. Only the Mitsubishi "Hyper Heating" units have a rated output at -25C (where it's coefficient of performance is about 1.8, not terrible, considering.) They self protect by turning off at about -28C, restarting only when the temperature rises to -25C again.

   The coolest specified cool temp output I've seen on any Daikin product is at -20C. They will keep running at temps lower than that, but would probably stop running before -25C. I'd consult with a Daikin engineer before buying if -25C is a common overnight low in your location.

   Weatherspark.com has temperature history datasets for tens, maybe hundreds of thousands of locations worldwide. If you're not sure how often it really dips that low in a particular winter, you can get a decent idea by zooming in on the coldest days of any recent winter. (The weekly or monthly blocky temps aren't really going to tell you much- you have to look at the hourly graph of the individual days that seem to be likely candidates.)

2. 
   user-1137156 | Mar 15, 2013 05:47pm | #2

   The heat output of a 12,000 BTU/h Mitsubshi Hyper heat has dropped below 9000 at -20c However the 18000BTU/h rated unit could still deliver a bit over 12,000 BTu/h at -20c Either unit will have the same minimum heat output (as I recall about 3500BTU/h). The cost difference is a few hundred $ I'd sure opt for the bigger unit.

3. 
   jinmtvt | Mar 16, 2013 09:32am | #3

   Erik: you are in BC mou mountains right ?

   I'd second going with a larger unit as the price difference is almost ridiculous.
   And with that low temp probably the mitsubishi since they have a specific design for our market with
   their hyper heat as stated by Dana.

   Would you post a picture of your "mountain view" ??
   :)

4. 
   user-1105327 | Mar 16, 2013 01:41pm | #4

   if i go with the mitsubishi, the more expensive unit, how concerned should i be about the SEER rating? perhaps the r2000 evaluator will advise me on that issue.
   i'll find some pictures for you, jin. our project is right beside the almost 4000m mt. robson!

5. 
   user-1105327 | Mar 16, 2013 01:51pm | #5

   dana, this is a screenshot of the weatherspark info from the nearest weather station (90km south) to our project.

6. 
   user-1105327 | Mar 16, 2013 01:53pm | #6

   sorry, it's not letting me attach the correct image. the weather station is in blue river british columbia, though...

7. 
   user-1137156 | Mar 16, 2013 03:48pm | #7

   Erick,
   You'll save far more in heating cost (ordinarily described by the HSPF rating, but it's tests aren't as extreme as your climate) than could ever be saved during air conditioning season. (which is what SEER is about) In other words accept the SEER the hyper heat offers knowing you made the best choice..

8. 
   user-1105327 | Mar 17, 2013 01:28pm | #8

   jerry, can't you get the same model but with different SEER ratings?

9. 
   jinmtvt | Mar 17, 2013 10:11pm | #9

   Erik: not with mitsubishi mr slim and hyper heat ( which YOU NEED )
   the different SEERs are from the size of the kit ( going from 26 @ 1/2ton down to 22 i believe )

   Jerry is spot on, the HSPF is what is important in your/our case up north,
   unfortunately, it is not something that can get much better than it already is because of the theoritical limits. I was told to expect approx 1.2COP for heating with the Hyper Heat @ -20c and donwnward ... but it goes up pretty fast to 3.0 near 0c which is where you will save alot
   since your temps should be higher than -10c in average during heating season :)

   still waiting for that picture ... 4000m Robson .. i need to move to BC in the future ...
   but you guys got no maple trees !! :(