Heat Pump

[buickanddeere]

What is with all these ductless AC units ? Why not install central air or a heat pump on the furnace and use the air ductwork in the house ?

 

[Bird]

Obviously you have never lived with a woman going through the change !!! :dance1::dance1:

Or had 25 female employees in 2 rooms.:laughing:

 

[RalphVa]

What is with all these ductless AC units ? Why not install central air or a heat pump on the furnace and use the air ductwork in the house ?

There are houses without duct work. Ours in NJ did not have any. Ductless would have been a good option, but didn't think about them. Not sure vendors had them available here back then.

The duct work is messed up between our 1st floor and basement; cannot add another zone to the main heat pump system. Wanted heating/cooling in the basement. While I was sick recovering from congestive heart failure, I was living in front of electric space heaters in the basement. Put 2 ductless units run off one controller for the 2 areas of the basement. Each main unit can handle up to about 7 inside units. You just have to cut about a 2 to 4 inch O.D. hole in the wall and run refrigerant lines to the inside unit where you want it.

They are the most efficient and no problems with backup heat (none needed unless you're far north). Our ductless runs off the generator when power is out. They're also utterly quiet outside. You only hear the fan running inside, about the same as fast speed from normal duct discharge.

Ralph

 

[hslogger]

What is with all these ductless AC units ? Why not install central air or a heat pump on the furnace and use the air ductwork in the house ?

Different strokes for different folks. for instance. I have a ducted indoor wood furnace for a two story farm house. Also a single wood stove. Up until four years ago I heated with wood exclusively. The ductless systems are zonal and their efficiency is far beyond what a ducted blower system can provide for us in our climate. BUT, in the winter if it is in the single digits and teens, we fire up the wood stove to help out. Ducted systems have loss even though you insulate the ducting. Some say that is a wash because the escaping heat will still heat the underneath of the house.

So be it. The ductless system has very little resistance in blowing straight out of the inside wall mount unit. There is no loss what so ever. They are gaining in popularity and in the long run, we will see, years down the road how they stack up in the reliabilty column. So far we have found them to be clean, quiet and efficient.

I will never tear out the wood furnace and the ducting, but the Mitsubishi set we have blows the doors off of it in operation for us.

 

[buickanddeere]

Different strokes for different folks. for instance. I have a ducted indoor wood furnace for a two story farm house. Also a single wood stove. Up until four years ago I heated with wood exclusively. The ductless systems are zonal and their efficiency is far beyond what a ducted blower system can provide for us in our climate. BUT, in the winter if it is in the single digits and teens, we fire up the wood stove to help out. Ducted systems have loss even though you insulate the ducting. Some say that is a wash because the escaping heat will still heat the underneath of the house.

So be it. The ductless system has very little resistance in blowing straight out of the inside wall mount unit. There is no loss what so ever. They are gaining in popularity and in the long run, we will see, years down the road how they stack up in the reliabilty column. So far we have found them to be clean, quiet and efficient.

I will never tear out the wood furnace and the ducting, but the Mitsubishi set we have blows the doors off of it in operation for us.

The ductwork is outside of the house ?

 

[goeduck]

I have a traditional heat pump with the outdoor unit being a Carrier and the indoor unit being a Trane. I don’t know what the story on that is, it was this way when I bought it. They obviously matched the set and it seems to work fine. We never use the AC (other than when I bought the house the inspector did) since our climate is moderate and I live on the salt water (big heat/cool stabilizer). In the winter the heat pump is backup to wood heat. In the spring/fall it is the only source of heat we use.

 

[hslogger]

All the ducting for the furnace is in the house underneath the bottom floor, and insulated well. The trunk that goes upstairs is not insulated. The furnace is located in the house. I was planning on moving the furnace OUT of the house but when the time came to do it, I decided to go with the ductless system, and less firewood cutting.

 

[buickanddeere]

All the ducting for the furnace is in the house underneath the bottom floor, and insulated well. The trunk that goes upstairs is not insulated. The furnace is located in the house. I was planning on moving the furnace OUT of the house but when the time came to do it, I decided to go with the ductless system, and less firewood cutting.

A crawl space open to the outdoors instead of a basement ?

 

[hslogger]

yep. no basement here. House has about forty inches of clearance from bottom of joists to dirt . Continuous concrete foundation and footers, with vents in the concrete that I seal up in the winter. Far from 100percent airtight, but the place breathes nicely and no condensation underneath due in large part to heavy plastic as a vapor barrier on the dirt.

 

[goeduck]

yep. no basement here. House has about forty inches of clearance from bottom of joists to dirt . Continuous concrete foundation and footers, with vents in the concrete that I seal up in the winter. Far from 100percent airtight, but the place breathes nicely and no condensation underneath due in large part to heavy plastic as a vapor barrier on the dirt.

That is how my house is built. Some like a basement but I am glad to not have one. But I moved from a 1949 house that had a full basement that smelled like a basement even though I had a small fan exhausting it 24/7/365 for 28 years. Tried many things, just could not get rid of that basement smell.

 

[retired007]

Thanks for the discussion. Very helpful and appreciated.

 

[MacLawn]

"Kumo cloud app...". Yep, kumo means cloud in Japanese. Like I said, these split units were developed in Japan, I've used them there since 1981. Had 5 in last house, will be installing one in northeast Japan house next month. More than just Mitsubishi available there, and just as good. Mitsubishi just hit in early and about took over American market, but Toshiba, Sharp, Daikin, Fujitsu, etc. are all good products there. House and apartments in Japan have no heat/air, nothing. So you always have to provide your own. No ductwork. The last house with the 5 units, we also heated with gas and kerosene. Heat pumps, gas, and kerosene trying to stay warm! We did, at about $500-600 a month for it all in a 750 sq. ft. house. I reckon with ducts already in my house here in GA, I'll just stay with American kind of heat pump. Thinking of mini split in separate office building.

 

[buickanddeere]

yep. no basement here. House has about forty inches of clearance from bottom of joists to dirt . Continuous concrete foundation and footers, with vents in the concrete that I seal up in the winter. Far from 100percent airtight, but the place breathes nicely and no condensation underneath due in large part to heavy plastic as a vapor barrier on the dirt.

We like a basement for laundry, water heater , well pressure tank, furnace , freezer , barn clothes entrance , extra washroom/shower , fireplace , firewood storage and TV. A place to hang up hockey gear to dry etc.
Not safe to have utilities outside where they can freeze .


It is true that unless designed and built properly from scratch a basement can suffer moisture problems . Has to be a couple feet of drainage stone with gravity tile drainage under the entire basement floor and out last the footings 2-3 feet . with drainage stone from footings to surface . There has to be insulation between the floor and the drainage stone . The walls must also have external insulation from the footings to the almost the surface .

 

[Sigarms]

They are the most efficient and no problems with backup heat (none needed unless you're far north). Our ductless runs off the generator when power is out. They're also utterly quiet outside. You only hear the fan running inside, about the same as fast speed from normal duct discharge.

Ralph

Ralph

You're incorrect per no issues with backup heat.

Each ductless manufacturer has speciffic ratings per heating capacity.

I know numerous contractors in North Carolina who have sold "9,000 BTU heat pumps" per mini splits where the load requirements required 9,000 BTU/h of heating at 20 degree outside air temp, and those homeowners/contractors have been burned because the heating capacity is lacking at that outdoor temp.

Don't assume heating is only needed "up north". I'm in NC and I require 500 more heating hours each year than cooling hours per my HVAC system.

You MUST know the capacity of each system to ensure it will achieve both your cooling and heating requirements.

Low ambient cooling is in the same boat when it comes to commercial cooling required below 20 degree outside air temp.

And as far as being "most efficient", the fact is "ductless" is kind of cheating per it's rating because of no duct work being involved. The reality is most major US manufacturers actually outperform mini split manufacturers "ducted" systems.

 

[Sigarms]

I reckon with ducts already in my house here in GA, I'll just stay with American kind of heat pump. Thinking of mini split in separate office building.

The fact is this is why Daiken bought out Goodman, to gain access to the American market (added the fact that Goodman had been for sale for years with no takers).

Johnson Controls has formed a partnership with Hitachi (ductless), and Trane has now formed a partnership with Mitsubishi.

You want to know where the future is going? The ability to connect traditional American ducted systems with mini splits with the SAME outdoor unit. At this point, one US owned manufacturer is already working on this for the last year. Close, but not out yet. Personally, I can't wait.

On a side note, American inverter split systems (and even some multi stage compressor systems) have gotten very well at heating without strip heat. I personally know and had monitored a couple of systems per my own curiosity per some manufacturers claims, and have had conventional split ducted heat pump systems pushing over 105 degree air temperatures when it was below a 10 degree outside air temp (without running strip heat). Not as good (high) as some mini splits I've monitored, but again, when you're dealing with ductwork, you're already at a disadvantage.

Have to keep in mind, in the "old days", a heat pumps bad rap was even though it heated, it didn't feel "hot". That's because generally those systems would only blow sub 98 degree air (inside) when it was cold outside, which is colder than the human body, so the air felt "cold" even though you could maintain say 72 degrees when it was 30 outside.

 

[kenmac]

G5CD-AU54-3_Submittal.pdf - Google Drive

G5HP-CA6-3_Submittal.pdf - Google Drive

Hopefully, My unit will be here in the next few weeks and I can get it installed

 

[goeduck]

You want to know where the future is going? The ability to connect traditional American ducted systems with mini splits with the SAME outdoor unit. At this point, one US owned manufacturer is already working on this for the last year. Close, but not out yet. Personally, I can't wait.

So split duct mounted units on main branches with all refrigerant lines connected and to the outdoor unit? Would one recover from another? That would be interesting on a retrofit basis. I assume you would still need a main blower in that case.

 

[Sigarms]

G5CD-AU54-3_Submittal.pdf - Google Drive

G5HP-CA6-3_Submittal.pdf - Google Drive

Hopefully, My unit will be here in the next few weeks and I can get it installed

Ken

Correct me if I'm wrong, but that's not a VRF system, it's just a inverter mini split with a one piece multi position ducted air handler?

I've stayed away from Gree, and Lennox along with Trane has dropped them as their "private label" in the past, but I'd sincerely be curious as to the actual heating capacity at lower outdoor units. I'm assuming the Gree is like the Mitsubishi one piece ducted air handler, and strip heaters can be used, but at least in NC, you're kind of defeating the purpose if you're running a inverter system and have to use strip heat for back up heat.

Edit - re looking at the submittal your provided, it states the compressor is "VRF". I'm guessing that's Gree's lingo for inverter.

 

[Sigarms]

So split duct mounted units on main branches with all refrigerant lines connected and to the outdoor unit? Would one recover from another? That would be interesting on a retrofit basis.

You have a 20 year old ducted system that needs to be replaced.

Contractor comes in and replaces air handler or gas furnace/coil, along with outdoor unit, and then can add indoor mini splits off the same outdoor unit.

The issue is the US market is the only market in the world that really uses ductwork as we know it (the few large commercial jobs I've been involved with outside the US was using VRF mini split systems).

EVERY mini split manufacturer sold in the US (over 80 of them at least in the US now), and not ONE of them is actually made in the United States, all imported.

A major portion of the price differences you see per mini splits sold in the US is directly due to US support of the product line per technical help/training and parts availability.

The one big downside to multiple indoor units (multi zone mini splits) that contractors rarely address is multiple suction and liquid line refrigerant ball valves because if one head goes down, the entire system goes down unless you have every line isolated. Same issue would hold true for the newer "technology" coming out.

 

[goeduck]

You have a 20 year old ducted system that needs to be replaced.

Contractor comes in and replaces air handler or gas furnace/coil, along with outdoor unit, and then can add indoor mini splits off the same outdoor unit.
.

Would those mini splits be ducted? What would the air handler do if there were mini splits installed?