Posted By Dana1 on 24 Apr 2013 06:22 PM
I have some better-off in-laws in central MA who built a $1MUSD+ house 8-9 years ago with nice radiant floors, yet NO air condition, at barely better than code-min for R values & U-factors.

"...I still have two sets of in-laws heating with $4+ oil, and two others heating with electric baseboards & 15-18cent electricity. You can't push a string, even when the solutions are dead obvious, affordable, and dangled in front of them...."

"My in-laws kept their crummy but functioning low-efficiency heating system, put about 20-25 grand into the building envelope, reducing heating fuel use by over 35%. "

Am I the only one who gets confused by the amount of in-laws you have?

They're the only heat pump techology currently out there that can dehumidify even in heating mode

There is also the new Bosch with the reheat coil, also the Climater has that technology, and the Waterfurnace commercial units.

"Am I the only one who gets confused by the amount of in-laws you have?"

Nope, even I'M constantly being confused by it myself! :-)

Mi esposa has 7 siblings, most of whom live within 40 minutes drive of my house. (The megabuck-house peops are one of the sets heating with $4 oil. The ones with the low-efficiency legacy heating system are on the gas grid. Neither of them has central air conditioning. The other oil-burner family has AC, but they're the only ones who do.) Yes, its a whole lot o' in-laws, and family gatherings can become mob scenes.

I hadn't heard of the Bosch units, or the Climater. What are the smallest tonnage units they have with those features?

sbeausol: It's too late to register, but there's a ductless seminar being held today by the NESEA folks, hosted at Mitsubishi's training center in Southborough (just off Rt 9, a bit west of Framingham.) I'm sure there will be a few competent practitioners in attendance- maybe you can crash it, if you promise not to eat all the munchies(?):

http://salsa3.salsalabs.com/o/50231/p/salsa/event/common/public/?event_KEY=70663

In my limited experience the average local ductless installer in MA isn't any more competent than the abyssmal average of any other HVAC contractor. It's better to run the load calculation numbers yourself (or hire an energy-nerd consultant) and tell THEM what you need, and where it needs to go. Many seem to treat it as they would an air-conditioner, which won't need to run when there's 2' of snow on the ground. It amazes me the number of mini-splits I see ground-mounted it against the house where it'll get buried in drifting snow or roof avalanches and need to be dug up after every nor'easter, but some are starting to get it, bracket mounting it on the wall 3-4' off the ground, protected from cornice-fall by overhanging eaves or a small purpose-built shed-roof.

In my limited experience the average local ductless installer in MA isn't any more competent than the abyssmal average of any other HVAC contractor.

The thing that gets me is that MA is regularly considered one of the top 5 best educated states in the US. The amount of strong science and engineering in the Boston area rivals any place in the world. Yet finding a competent HVAC contractor is harder than finding a Yankees fan at a local bar...

Yabbut, finding the Yankee fan is EASY, since everyone is glaring & screaming in their direction. :-)

Very few HVAC contractors will do the math without prompting, and even when they do they're not always competent at it, and I don't think it's just a New England phenomenon. With GSHP the financial downside of NOT doing the math is pretty high, so my expectations there are higher than for those selling conventional systems. Most installing mini-splits are in the air conditioning biz, and will as often as not size the system with such hard math rules as, "Lessee, couple thousand square feet, divided by five hundert-a-ton, that's gonna be four tons." (Which is probably how the behemoth at my house was chosen.) The upfront cost of oversizing isn't on those systems isn't compared to GSHP, but they're neither as comfortable nor efficient as a right-sized version. The same would be true if you oversized mini-splits by more than ~50%.

The mini-split manufacturers have training programs and "master installer" lists that can be found on some of their installer-finder websites, which is probably a reasonable first level of filtering. But I'd still strongly advise using your own load calculations to vet theirs, even when they run more reasonable-looking load calculations than dumb rules of thumb.

A few weeks ago I was talking to a high performance building contractor who has given up on all of the Mitsubishi installers in the area after multiple instances of seeing them install heads that weren't compatible with the compressor units. That's mostly a length of catalog problem, where you may have 17 different options for say, a 9000BTU/hr head, but they don't all have the same communication protocols as every compressor system. When you're in the 1-3 heads territory and sticking with the standard heads usually bundle with the system you won't run into that issue- it' s when you're looking a flush to ceiling cassettes or the mini-ducted heads etc that they won't always work. The other manufacturers have far fewer options, but also far fewer compatibility issues. (It seems pathetic that the HVAC contractors can't or won't read the specs better than the client though. :-( )

Posted By Dana1 on 25 Apr 2013 10:45 AM

I hadn't heard of the Bosch units, or the Climater. What are the smallest tonnage units they have with those features?

I believe CM and Bosch are 2 ton, WF goes down to single stage and 3/4 ton.

If I were doing a from scratch HVAC design, I'd investigate a hydronic system with:

1) air source or geo heat pump
2) water tank large enough to provide for off peak rates or more efficient outdoor temperatures (ASHP)
2) wall mounted panel radiators, perhaps with fins or fans
3) drain pans such that the radiators can provide cooling
4) Standard HRV ducting.

Hopefully these radiators would be inexpensive enough (aluminum filled plastic?) that there could be one (or more) in every room. Perhaps a minimum of two to simultaneously provide heating and cooling (sometimes needed for high latent loads).

Room loads would be low enough (super insulation) that the panels could be of reasonable size (say 4' wide by 8' tall) and still provide for efficient operating temperatures.

Posted By docjenser on 25 Apr 2013 01:17 PM

Posted By Dana1 on 25 Apr 2013 10:45 AM

I hadn't heard of the Bosch units, or the Climater. What are the smallest tonnage units they have with those features?

I believe CM and Bosch are 2 ton, WF goes down to single stage and 3/4 ton.

The smallest WF is small enough to potentially let your potable-water well do double duty, if your loads are that low!

But would it come in comparable to or cheaper than a 3/4 ton Quaternity, in any realistic scenario?