Wife wants mini-split for bedroom/hallway, options

Post in 'It's a Gas!' started by mass_burner, Apr 3, 2014.

  1. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    Okay, so she wants this for those rare occasions when heat/humidity get so bad we need an AC. We have awning windows, so window unti not an option. I would like a unit to heat also, in winter I run wood stoves in the main living areas, LR/KIT, family room, DR all open floor plan, the furnace for these zones barely ever comes on. At night we close the one door separating the "common area" from the bedrooms/bathrooms. Overnight in this area is where we use most of the oil.

    Do MS's do a good job of cooling and heating? Would electric be preferable to gas?
     
    Collapse Signature Expand Signature

    Helpful Sponsor Ads!





  2. AK13

    AK13
    Expand Collapse
    Feeling the Heat

    Joined:
    Oct 15, 2010
    Messages:
    254
    Likes Received:
    34
    Loc:
    Seacoast, NH
    Do you heat with natural gas or propane? Based on current prices in our area the natural gas is most likely cheaper than heat pump. If propane, then heat pumps for sure.

    I would get a heat pump vs. cooling only unit anyway though. The heat pump hardly costs any more than cooling only and would be ideal for shoulder season heating and maybe even cheaper than natural gas when temps are in the 40's and above.

    If you want maximum heating performance then Mitsuibshi Hyperheat is the way to go. If low temp heating isn't a priority then a unit from Mitsubishi, Fujitsu or Daikin would be my recommendation. IMO those are the top tier brands.
     
    Collapse Signature Expand Signature
  3. #3 mass_burner, Apr 3, 2014
    Last edited: Apr 3, 2014
    mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    We have NG hookup, but only use it for cooking, but its there. No propane.
     
    Collapse Signature Expand Signature
  4. AK13

    AK13
    Expand Collapse
    Feeling the Heat

    Joined:
    Oct 15, 2010
    Messages:
    254
    Likes Received:
    34
    Loc:
    Seacoast, NH
    Yikes, you have NG in the house and you are burning oil! I bet you'd have a very good payback to swap out your oil furnace for an NG one.

    A mini-split heat pump would still be a nice way to add A/C to the house. But in terms of a payback your best "investment" would be to heat with NG instead of oil.

    How do you heat your hot water?
     
    Collapse Signature Expand Signature
  5. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass

    The PO upgraded to a new Buderus burner/storage tank in 2007. Estimate to switch to NG, even with subsidiies, was 14k. I couldn't see ripping out a very efficient burner and paying 14k to do it. I put in another insert instead. I've used 215 gals since 11/5/13, probably can make it to 11/5/14 with 50 more gals. Hot water with oil too, but that takes very little.

    Does a heat pump have to run on propane?
     
    Collapse Signature Expand Signature
  6. Ashful

    Ashful
    Expand Collapse
    Minister of Fire

    Joined:
    Mar 7, 2012
    Messages:
    8,716
    Likes Received:
    3,627
    Loc:
    Philadelphia
    I have installed a few minisplits, all Mitsubishi. I have one heating and cooling my music studio right now, with auto change-over. They do the job, and they're about as efficient as any other heat pump option. A propane or nat.gas backup is NOT an option with Mitsubishi, but perhaps others. They do have some nice hidden ceiling, wall, and toe-kick indoor units / evaporators, in addition to the standard wall mounted units. I'm sort of wishing I had done a ceiling mounted unit or two in my most recent install, instead of the standard wall unit, but I don't have much experience with those.

    One issue with any minisplit is the drain. Installers have told me they want a pretty aggressive and continuous downward slope on that drain. I don't know why, but suspect they must have had some drain issues in the past.
     
    Collapse Signature Expand Signature
  7. maple1

    maple1
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 15, 2011
    Messages:
    6,434
    Likes Received:
    1,116
    Loc:
    Nova Scotia
    Heat pumps run on electricity.
     
    Collapse Signature Expand Signature
  8. AK13

    AK13
    Expand Collapse
    Feeling the Heat

    Joined:
    Oct 15, 2010
    Messages:
    254
    Likes Received:
    34
    Loc:
    Seacoast, NH
    Ahh, I see. You don't have a furnace. You have a boiler. Furnaces heat air. $14k sounds very steep. But regardless if you are only burning 200+ gallons of oil a year then I agree that there is not a reason to swap out a nice Buderus boiler.

    Condensate drains can be an issue for some installs.If you are on an exterior wall then its easy. If on an interior wall and over basement then probably easy since you can go down the wall and find a place to tie in in the basement (laundry standpipe, etc).
     
    Collapse Signature Expand Signature
  9. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass

    We have both options, we're thinking of putting it on an exterior wall in the master BR; but we also have full basement with lots of headroom. I was thinking at the end of the hallway for more even distribution. I don't suppose there are models that can cool/heat and humidify.
     
    Collapse Signature Expand Signature
  10. velvetfoot

    velvetfoot
    Expand Collapse
    Minister of Fire

    Joined:
    Dec 5, 2005
    Messages:
    8,874
    Likes Received:
    634
    Loc:
    Sand Lake, NY
    Would the cool air sink downstairs before it cooled off the master bedroom?
     
    Collapse Signature Expand Signature
  11. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    downstairs? we don't have a second story.
     
    Collapse Signature Expand Signature
  12. velvetfoot

    velvetfoot
    Expand Collapse
    Minister of Fire

    Joined:
    Dec 5, 2005
    Messages:
    8,874
    Likes Received:
    634
    Loc:
    Sand Lake, NY
    Well, then I guess it won't sink downstairs. :)
     
    Collapse Signature Expand Signature
  13. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    The specs on the M-series heat pump gives the btu's, but how can I tell how big a space this will heat/cool. I'm wondering if a centrally located single unit at the end of the hallway (at the opening to two bedrooms) will heat/cool those bedrooms, hallway, and adjoining baths.

    Cooling:
    Rated Capacity 9000 Btu/h (2.64 kW) *1
    Capacity Range 2800 - 9000 BTU/h (0.8 - 2.6 kW)

    Heating at 47° F
    Rated Capacity 10900 Btu/h (3.2 kW) *2
    Capacity Range 3000 - 18000 Btu/h (0.9 - 5.3 kW)

    Heating at 17° F
    Maximum Capacity 12500 Btu/h (3.7 kW)
     
    Collapse Signature Expand Signature
  14. Ashful

    Ashful
    Expand Collapse
    Minister of Fire

    Joined:
    Mar 7, 2012
    Messages:
    8,716
    Likes Received:
    3,627
    Loc:
    Philadelphia
    Three possible ways to go at this:

    1. Heat loss calculations, based on assumed typical values (experience).
    2. IR camera and blower door test data.
    3. Experience with your existing system (how big is it? does it do the job? how many window units did it take to keep cool in July?).
     
    Collapse Signature Expand Signature
  15. AK13

    AK13
    Expand Collapse
    Feeling the Heat

    Joined:
    Oct 15, 2010
    Messages:
    254
    Likes Received:
    34
    Loc:
    Seacoast, NH
    There are no mini-splits that humidify. They DE-humidify though.
     
    Collapse Signature Expand Signature
  16. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass

    maybe while we're getting an HP estimate we can ask about humidifying in the winter. hate waking up in the night with dry nose/mouth. i have a portable humidfier on wheels but its pretty big, a tad noisy.
     
    Collapse Signature Expand Signature
  17. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass

    what about 15 * volume = BTU's needed
     
    Collapse Signature Expand Signature
  18. AK13

    AK13
    Expand Collapse
    Feeling the Heat

    Joined:
    Oct 15, 2010
    Messages:
    254
    Likes Received:
    34
    Loc:
    Seacoast, NH
    I've never seen that rule of thumb. Any idea what the basis is? You are basically saying 15 btu/hr/cubic foot. That is a new one to me. Is that sizing for heating or cooling?
     
    Collapse Signature Expand Signature
  19. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    saw

    saw it online, can't remember where. thought it would be familiar.
     
    Collapse Signature Expand Signature
  20. moey

    moey
    Expand Collapse
    Minister of Fire

    Joined:
    Jul 12, 2012
    Messages:
    1,323
    Likes Received:
    325
    Loc:
    Southern Maine
    There is no general rule when it comes to BTU's

    slant fin has a heat loss program its pretty good http://www.pvsullivan.com/Downloads.html I dont know why they no longer have it on their website they have a android/iphone app on there but not the windows version. Keep in mind garbage in garbage out.
     
    Collapse Signature Expand Signature
  21. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    okay, so here are the room sizes. all cielings 8'.
    1 BR, 12 x 12,
    1 BR, 15 x 20, including bath,
    hallway, 3 x 16
    bath, laundry, 12 x 7
    so that's 4608 cu ft.
     
    Collapse Signature Expand Signature
  22. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    so I did the calulator at Mitsubishi website and this came out:

    Cooling Capacity: 11100Btu
    Heating Capacity: 13600Btu
    SEER Rating Range: 15
     
    Collapse Signature Expand Signature
  23. mass_burner

    mass_burner
    Expand Collapse
    Minister of Fire

    Joined:
    Sep 24, 2013
    Messages:
    2,344
    Likes Received:
    394
    Loc:
    SE Mass
    estimate came in:

    option 1: 1 head unit: $5490 installed, MUZ-GE12NA / MSZ-GE12NA
    option 2: 2 head unit: $7455 installed, MXZ-GE12NA/ MSZ-GE12NA, MSZ-GE09NA
     
    Collapse Signature Expand Signature
  24. #24 peakbagger, Jun 20, 2014
    Last edited: Jun 20, 2014
    peakbagger

    peakbagger
    Expand Collapse
    Minister of Fire

    Joined:
    Jul 11, 2008
    Messages:
    2,478
    Likes Received:
    513
    Loc:
    Northern NH
    The equipment cost is around $2300 so the rest is installation and markup for a warrantee. At that sort of markup they can buy two and have one sit on the shelf in case your original one breaks down.

    I expect a skilled crew of two could do the install in four hours if they have the right tools. It took me about 12 hours and about 2 hours to purge the lines and pump them out.
     
    Collapse Signature Expand Signature
  25. AK13

    AK13
    Expand Collapse
    Feeling the Heat

    Joined:
    Oct 15, 2010
    Messages:
    254
    Likes Received:
    34
    Loc:
    Seacoast, NH
    I think you are being a big conservative there. You don't know what all is included in that quote, how long the runs are, etc. 8 man hours seems pretty optimistic to mount both units, run refrigerant piping, power wiring, condensate piping. Could be cutting and patching for line set installation (but I doubt it). You don't know if they are putting it on a nice raised stand or dropping it on pressure treated sleepers. Plus does your $2300 include the linesets, drain piping, breakers, wiring. Plus don't forget overhead. .

    Sure, you could do it cheaper DIY, but I think its wrong to imply that the contractor is making a killing with "that sort of markup". The pricing looks about right.

    OP, your outdoor unit model number for the multizone option looks wrong.
     
    Collapse Signature Expand Signature

Share This Page