Can we talk about heat pumps?

[Rembrant]

Originally Posted by vrmouseyd15b

I'm an HVAC installer / service tech since 1999. The "mini-split" equipment is almost like magic! It's rediculously efficient and quiet, low maintenance equipment (when properly installed). It's been all over the world forever, but like european fashions, it took a while to hit the U.S.


Obviously, this type of equipment will be more of an initial investment than your traditional HVAC system, but I can tell you that over the years, more and more people are starting to come around to this type of heating and cooling system, and NOBODY has complained about operating costs with these mini-splits.

Hey Victor,

Please don't take anything I'm saying here personal...I'm not trying to give anybody a hard time that's making a living at this stuff. I'm just curious, and would like more data than typical sales praise, that's all.

Just out of curiosity, what is the typical install cost of a ductless heat pump...lets say, for a house of 1500 sq/ft? I think my house is 1800...but that might include the garage, not sure. Now, not necessarily as a single heat source...but like they advertise around here, as "supplemental heating" in the "shoulder seasons".
I've talked to a few people, and they seem to spend around $3500 having one of these things installed...plus or minus of course.

And, what kind of lifespan to these units have?

Just curious,
Rem

[pgfpro]

Originally Posted by Rembrant

Hey Victor,

Please don't take anything I'm saying here personal...I'm not trying to give anybody a hard time that's making a living at this stuff. I'm just curious, and would like more data than typical sales praise, that's all.

Just out of curiosity, what is the typical install cost of a ductless heat pump...lets say, for a house of 1500 sq/ft? I think my house is 1800...but that might include the garage, not sure. Now, not necessarily as a single heat source...but like they advertise around here, as "supplemental heating" in the "shoulder seasons".
I've talked to a few people, and they seem to spend around $3500 having one of these things installed...plus or minus of course.

And, what kind of lifespan to these units have?

Just curious,
Rem

I would love to know a price too. Our house is 1200 sq ft.
Thanks Russell

[Cobb]

I got a goodman. You are dead on about the defrost cycle. Its usually followed by an air brake sound and aloud vibration as the fan stops, but compressor keeps going. Usually when its in heat pump mode and its near freezing its blowing smoke like so never seen the steam cloud.

Funny note, we had it checked up a few years ago. Was told we had a leak and was low 3 lbs of freon and needed to get it fixes. Still going with no problems.

Originally Posted by basjoos

My old Goodman heat pump used to defrost on a fixed schedule when running as a heat pump.

[vrmouseyd15b]

I'm just curious what the real details are on these ductless heat pumps? As I said above...all I hear is praise...from sales people to the people that buy them. I know many people that have purchased them, but I have not heard a single word from any of them after the fact...other than how much they love their heat pump. I never seem to hear anything on actual savings or ROI. People tell me that they work great....but it's like talking to that guy that just bought a new diesel VW and he tells you he's getting 60mpg....but in reality, the only reason he knows (or thinks that) is because the sales rep told him so...not because he actually checked and tracked it (in which case he'd find out he's only getting 50mpg).

First off, don't worry about hurting my feelings We're all here to help


I can't tell you how long to expect a mini-split to last, but I would guess12-15 years. $3500 sounds pretty fair if that's the whole job and you're taking care of a "great room" type addition. Installed cost can vary based on total btu's needed, number of indoor units, length of copper runs, ease of drain line runs, whether or not you want to see the refrigerant lines, ETC..
These types of systems are basically "custom built" to your comfort goals, and prices will vary greatly..


Trouble comapring these systems is they're load-based. They run to keep the settings YOU want. They are limited in their cycle rate by the rate of heat-loss that is specific to YOUR HOUSE. The house next door will be totally different looking at heat loss/gain from room to room, and that's how mini-split looks at it, not the conventional whole house temp set from one (poor) location!

Unfortunately, looking to find solid proof in numbers on standard systems - vs-mini-split is almost impossible.

What kind of MPG'S do you get driving in your car? Now tell me what kind of MPG'S I will get driving in your car? It's kind of like that, since the mini-splits are ECOMODDERS in their own right.
The seer rating system is based on constants. The mini-split's modulation is the secret to it's efficiency.

The real way to test would be to find the people who went "all in" and ONLY run mini-split after retrofitting from standard equipment, and hope that they have lots of utility reciepts to show "seasonal averages" of before and after the mini-split's installation for comparison. That could at least show you, on a house to house basis, the average savings. Good luck with that.

For the rest of us (me at least) the seer ratings speak for themselves. If I could afford it, I would rip out my furnace and go with Fujitsu's VRF system, but that's just not in the cards for me. I've got a 97% efficient 2 stage Rheem furnace that does me just fine


Thanks,
Victor

[Cobb]

I had a Trainn, it ran all the time and was only good for 30 degrees diff from the outside temp. Previous and current HVAC does 70 degrees in 100 outside or 0 outside.

Neighbor got one of those variable scroll(SP?) compressor hvacs. He keeps it 68 year round. It does deliver and is cheaper than before, but the outside unit runs sun up to sun down without cycling like our unit.

[vrmouseyd15b]

Originally Posted by Cobb

Funny note, we had it checked up a few years ago. Was told we had a leak and was low 3 lbs of freon and needed to get it fixes. Still going with no problems.

That's the trouble with the HVAC industry. Lots of "SCHEISTERS" out to screw people out oof their hard - earned money. Could go either way as far as whether or not you actully have a leak. (That tech may have been pushing a sale for his comission - trying to scare you with a long list of items to repair a leak on a system he couldn't gurantee OR HE MIGHT HAVE BEEN CLUELESS!) a roll of the dice either way

You will know when the system can't "keep up" with the load, or, depending on your system and what kind of stat you run, it may tell you at the stat that you are in "emergency heat" mode when you know it shouldn't be (I.E. +45F outside and running emergency heat). That would be an obvious indicator, as would an hour to make temp under the same conditions.

HVAC guys are like mechanics. If you find a good, honest one - keep him!


Thanks,
Victor

[Cobb]

Can you use these splits for a 3/4 bed room 1000-1200 sq ft home? Is it for whole house or 1-2 rooms?

[vrmouseyd15b]

Originally Posted by Cobb

Can you use these splits for a 3/4 bed room 1000-1200 sq ft home? Is it for whole house or 1-2 rooms?

all of the above. these units are available from I believe 18000 - 48000 buth (1.5 - 4 tons nominal cooling) the size of the unit would be based on the application.

This site follows the standard "manual j" load calculations, and it's pretty thorough. plug in as much info as you can for each room, and add them up!
WarmlyYours | Heat Loss Calculator

roosterk - p.m. me info. I work an hour west of home as it is (Bettendorf, Iowa - don't know if that's anywhere near you) you may want to go thru the calculator first to get an idea of what you'd need. There's no soldering in mini-split systems anymore (generally) they've all gone to a 33 degree (IIRC) flared compression type fittings.

The easiest way to figure out what you need, is to decide how you want to use the equipment. The quickest and least expensive solution with mini-splits is to supplement the existing HVAC system (cold additions, upper bedrooms, attached garage) and try to mount the indoor units on an exterior wall (making the lineset, drain, and electric all outside work - less mess inside!) and then mounting the outdoor unit at a centralized location from there. that will minimize the necessary power and refrigerant lines' length (and cost). Lastly, figure the outdoor unit's power requirements (the outdoor unit will power the indoor units and communicate with them) and bring the right power to the outdoor unit.

From there, it's just procedure, procedure, procedure

Edit: sorry this didn't click sooner - the "air brake" noise at the beginning and end of each DEFROST cycle is the reversing valve switching to and from cooling (generally they require 24v to "make" cooling - so if it fails you've still got heat) There is a slight "click" at first. that's the reversing valve. The "swoosh" is the refrigerant's pressure equalizing across the reversing valve and TXV(S) (Thermal eXpansion Valve or Valves)


Thanks,
Victor

[redneck]

.

Mini splits are available from 9,000 btu - 60,000 btu (3/4 - 5 tons)

Single zone (1 indoor head) mini split starts at 9,000 btu (3/4 ton) and go to 36,000 btu (3 ton)

Multi zone (2 indoor heads) start at 18,000 btu (1 1/2 ton) and go to (5 indoor heads) 60,000 btu (5 ton).

Multi zone indoor heads are available in varying sizes from 9,000 btu - 24,000 btu and can be configured in various combinations up to the rated output of the outdoor unit.


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