New Air Conditioner / Heat Pump time

[Isaac-1]

Well it looks like my 21 year old Duo-Therm rooftop heat pump / air conditioner has finally died (appears the compressor has went bad). So I am now shopping for a replacement. Any thoughts on the Recpro Houghton 15K heatpump ducted unit (I need a single zone ducted unit), all the online videos, etc seem to show the non-ducted model? Any others I should keep under consideration? I want a heat pump, and preferably one that works at lower temperatures than my current unit which cuts off when temperatures drop below 38F. The Houghton claims the heat pump to work down to at least 30F, some sources say 23F. I would consider the Dometic/Attwood Air Command unit, but it claims the heat pump only works down to 45F which is nearly useless since our coach is fairly well insulated and we rarely need to turn on the heat on nights where the temperature only gets down into the upper 40's.



thanks

[MrMark52]

Watching

[Mudfrog]

Interesting to read the "down to at least 30°F" claim. I know there are anomalies out there but I didn't realize there was a heat pump designed to do that.

I'm watching this one as well!

[MrMark52]

It’s been a few years since I taught this - but I found a good website that to me appears to be pretty straight forward and explains heat pump use at the 50,000 foot level.

https://learnmetrics.com/heat-pump-e...erature-graph/

Once you get your head around what the guy says and the metrics of a heat pump - you can then decide which unit you would want to move forward with, if at all.

[jharrell]

Originally Posted by Mudfrog

Interesting to read the "down to at least 30°F" claim. I know there are anomalies out there but I didn't realize there was a heat pump designed to do that.

There are a lot of modern heat pumps for home use that work well down to -10F, RV heat pumps are very behind best current designs.

https://carbonswitch.com/do-heat-pum...-cold-weather/

[jharrell]

Originally Posted by MrMark52

It’s been a few years since I taught this - but I found a good website that to me appears to be pretty straight forward and explains heat pump use at the 50,000 foot level.

What seems to trip people up is the difference between temperature and heat. I think it make more sense if you think in terms of absolute zero, the coldest temperature physically possible about -460F.

-0F is still 460 degrees F above absolute zero, there is a lot of heat in the air even when its what we as humans perceive as cold. Heat pumps capture that heat from the outside air, increase its temperature by reducing its volume with a compressor, and pump it inside. Heat pumps are basically solar assisted heating devices since the outside air is heated by the sun, even in cold weather.

The great thing is they work in reverse and provide air-conditioning!

[Harry B]

Originally Posted by Isaac-1

Well it looks like my 21 year old Duo-Therm rooftop heat pump / air conditioner has finally died (appears the compressor has went bad). So I am now shopping for a replacement. Any thoughts on the Recpro Houghton 15K heatpump ducted unit (I need a single zone ducted unit), all the online videos, etc seem to show the non-ducted model? Any others I should keep under consideration? I want a heat pump, and preferably one that works at lower temperatures than my current unit which cuts off when temperatures drop below 38F. The Houghton claims the heat pump to work down to at least 30F, some sources say 23F. I would consider the Dometic/Attwood Air Command unit, but it claims the heat pump only works down to 45F which is nearly useless since our coach is fairly well insulated and we rarely need to turn on the heat on nights where the temperature only gets down into the upper 40's.



thanks

I installed the Houghton 15k btu heatpump/AC last summer to replace the noisy 7 mo. old Mach 15.
It is much quieter, cools great and provided warm air even at an ambient temp of 29 degrees yet.
It has a defrost cycle that allows it to work that low just like some of the house airconditioners do.
It also has dehumidify cycle to get the moisture out of the RV that works great.
I really like the remote control that comes with it. One negative I have is that in cooling or heating mode it does no display the actual reached tempurature but the set temperature instead. Otherwise a very nice unit. Pretty pleased with the purchase.

[Isaac-1]

Harry, one thing I am not clear on, does the Houghton unit provide relay output control to operate the propane furnace, or are you forced to have a separate thermostat to control your propane furnace?

[Harry B]

It requires a seperate thermostat for the furnace.
There is no fiscal way to connect to the Houghton AC since it comes with its own wireless remote to control it

[MrMark52]

Originally Posted by Isaac-1

Harry, one thing I am not clear on, does the Houghton unit provide relay output control to operate the propane furnace, or are you forced to have a separate thermostat to control your propane furnace?

Originally Posted by Harry B

It requires a seperate thermostat for the furnace.
There is no fiscal way to connect to the Houghton AC since it comes with its own wireless remote to control it

Wow! A dual fuel system for a MoHo - am thinking that might be a first!

Shouldn’t be that hard to do if you can find a 1 stage cooling/2 stage heat thermostat that will run on 12 volts (unless the remote for the Houghton is also the thermostat, which I doubt).

Stage 1 heating would be the Houghton, stage 2 and/or Emergency backup heat would be the LP furnace.

Only issue I bet you’ll have is getting a 6 wire control cable between the thermostat and the Houghton (assuming your thermostat already controls both A/C and LP heat.

Neat idea! You ought to win some type of MoHo energy ingenuity award.

[SteveJ.]

Originally Posted by Isaac-1

Well it looks like my 21 year old Duo-Therm rooftop heat pump / air conditioner has finally died (appears the compressor has went bad). So I am now shopping for a replacement. Any thoughts on the Recpro Houghton 15K heatpump ducted unit (I need a single zone ducted unit), all the online videos, etc seem to show the non-ducted model? Any others I should keep under consideration? I want a heat pump, and preferably one that works at lower temperatures than my current unit which cuts off when temperatures drop below 38F. The Houghton claims the heat pump to work down to at least 30F, some sources say 23F. I would consider the Dometic/Attwood Air Command unit, but it claims the heat pump only works down to 45F which is nearly useless since our coach is fairly well insulated and we rarely need to turn on the heat on nights where the temperature only gets down into the upper 40's.



thanks

Ike, I found this from Recpro sold through Amazon.

https://www.amazon.com/RecPro-Condit.../dp/B08LZX88JM

[Isaac-1]

Steve, that is the one I am looking at, but the price is $100 less buying direct.

[hypoxia]

RP-AC3501 Non-Ducted Specs on page 17
Rated Cooling is 27° C (81° F) at 35° C (95° F)
Rated Cooling is 19° C (66° F) at 24° C (75° F)
I didn't find the ΔT for the competition

[MrMark52]

Just an FYI on RecPro, and different appliance altogether - a convection/microwave.

Bought it, it shipped to us. Installed as a replacement to the original Sanyo m’wave that had failed.
Worked good as the coach sat in the driveway.
Two weeks later, head to a wine festival across town for 3 nights. Left wife and 2 daughters for a girls night the first night.
They put a lasagna in the m’wave, started it cooking.
When done, they couldn’t get the m’wave door open. Both daughters, who are mechanically inclined over their mother - desperately wanted their Mom’s home made lasagna. They found some tools, and took the door off the m’wave, got their lasagna out, reassembled the unit and reinstalled back into the cabinet.
When I arrived the next day, they told me the story of rescuing their lasagna.
The next week, I tore into the m’wave.
What a piece of junk! Built just like most m’wave, but cheaper. If the unit was made of 28ga clad steel it would surprise me. The chassis was so weak that even the packing that the unit was shipped in couldn’t prevent the chassis from warping.
Called RecPro - told them of the issue - “We don’t have any more units and don’t know when we will get any”. Stalemate. After a few days, I asked “what are we going to do?”. They said “we’ll refund your money”. Within days a credit showed up on my credit card.
They never asked for the old m’wave back.

Moral of the story - I don’t think RecPro manufactures anything, they just cut a deal with a private label manufacturer who (from what I know about in 40+ years being around appliance manufacturing) buys from manufacturers whose design criteria falls short of the robustness needed for the products they manufacture.