Inverter heat pumps?

unclejohn

Anyone install the new inverter heat pumps or A/C units? Carrier calls them Greenspeed and Lenox has the xp25. Have a customer that is interested in one. I tend to shy away from the new stuff for the first few years.

Bob Bona_4

They've been around a while now. 7-8 years anyway. I've been doing Fujitsu and Mitsubishi. So far so good, they are at the point now that they heat in 0 degree outdoor. I do a lot of them in bonus room over garage projects, studios etc.

Harvey Ramer

I have had good luck with Daikin units. They do a good job and people like them.

unclejohn

I know the smaller units have been around. this is a five tone heat pump, that's a lot of juice to put through a circuit board that sits outside.

SWEI

Rheem has two new lines coming this summer.

Tinman

I've used the Mitsubishi units and 1 LG unit (customer insisted)...no problems on both accounts.

SWEI

I believe the need was for conventional ducted splits, for which we don't have a lot of VRF options (yet.)

Tinman

Duly noted. They'll probably be the norm rather than the exception in 5 years?

SWEI

Almost certainly. Two out of Rheem's three new heat pump lines are inverter driven (one out of three for the A/C's.) The difference in capacity alone will make it a no-brainer for the heat pumps around here. I'm looking forward to having another option for LPG furnace replacements.

John Mills_5

In conventional splits, you have the top models with variable speed scrolls, then you have the mid models which have inverter rotaries though they have 2-5 stages instead of variable. Carrier & Nordyne have these units, they don't run below about 10°.

Mitsubishi showed a conventional ducted air handler at AHR that can be used with the Hyper Heat outdoor units. That would be nice, probably pretty salty!

My concern is airflow if you aren't zoned, especially cooling a large house. We have enough trouble cooling a 2 story upstairs with a single stage. You get a variable speed running 40%, that's going to be a HOT upstairs. Not much cold air is going to find its way upstairs, lots easier to go to the registers closest the air handler.

Matt_67

We installed one of tranes new variable speed heat pumps in the upper peninsula of Michigan. Had one hiccup with defrost settings but a firmware update fixed the issue. It's a somewhat complicated system with a hydronic heating coil and wood boiler or fuel oil boiler backup. It heated the house through 8 degree overnight temps recently with no backup usage - my calcs had predicted 19 so the performance is good. Pretty nice setup so far.

unclejohn

Moot point now since the customer went with a geo thermal unit.

Eugene_Silberstein

Geothermal is definitely the way to go, if you have the space!

SWEI

Unfortunately, water-source heat pumps make up such a small percentage of the market that they typically lag the ASHP's by 3-5 years on technology.

unclejohn

Well I thought it was a bad choice since I don't install geo thermal.

Jack

Eugene, I have to disagree. Yes, geothermal is great, if you have the money. Also, if you are willing to take my and everyone elses money for the tax credits. It is a system for the wealthy because they can come up with the up front cost and have the space to do the ground work. Most rebate and tax credit dollars are gone but geothermal maintains them. Get rid of the federal money for them and that business will collapse, immediately, except in large commercial buildings where it is a great fit. I was installing geo back in '78 and it was unique, to say the least. Today, I can get within a few inches of the efficiency of the GSHP's with my mini-splits at a fraction of the cost. When you take into consideration the zoning aspect I actually probably gain. For instance, I only run the evaps in the bedrooms in the summer and for only short times of the evening or night for sleeping comfort. I haven't run them for heat at all in the 3 yrs I've been in the house. Actually my daughter did when the baby was here, but those aspects of the economical use add up too. My upstairs heat is provided by the Rinnai Energysaver we have in the first floor den that rises to the second floor. I have a 12 kbtu and a 15kbtu in the rest of the first floor. 25 and 21 seer and 12 hspf respectively. Best of all, it is "net to the space".

I thought it funny at the IBS and AHR shows that all the unitary manuf are touting their private label mshp's. The ability to eliminate ductwork, flex duct especially, is huge in the bigger sense, given how poorly it is installed and the leakage. As well, by eliminating the ducting in my home I gained two closets and the storage space under the stairs.

Mini-splits are not the American way, but whenever I look at anything energy wise, I see that we are the only people in the world who heat and cool by blowing air through tubes. I have to ask if we are right or if the rest of the world is right. From an energy perspective I think it is usually the rest of the world that is right.

bio_guy

Mitsu's hyper heat system is pretty slick. Here is the best description I have seen so far:

http://mitsubishielectricengineer.com/wp-content/uploads/2014/06/Mitsubishi_Electric_Engineer_Winter2012.pdf

One characteristic that I really respect with my mini split inverter units is the lack of start-up power surge. After a hurricane-associated power failure, running mine with a portable genset, I could not get the genset to sag when I turned on the mini-splits. controlling them with the remote, or turning on the breaker. Over a minute or so I'd hear the volume of the exhaust note increase, but not a typical sag like when the refrigerator or freezer kicks on.

I understand that Daiken is now making some of their equipment with DC compressor motors.

unclejohn

I think most American homes are too big for mini splits for that to really catch on. By the time you run 10 or 15 evaps your cost are up there. Unless we all go those mini one room homes which is not for me.

bio_guy

Open floor plans are still in vogue. That helps keep the unit # down. If my marriage is to survive, I need doors to hide behind and the wife needs door to slam when she gets mad.