HVAC Heat Pump

[freebeard]

...now to prototype my game-changing product...

Have a look at Tesla's Octovalve.

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The Tesla Octovalve is a key component of the Model Y's heat pump system, designed to efficiently manage the flow of coolant for heating and cooling various vehicle systems. It features a compact design with multiple ports and is controlled by an electric motor, allowing for precise thermal management in the car.
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[JSH]

Originally Posted by redpoint5

Those CCHP, and heat pumps in general are a racket. A heat pump has a couple extra valves or something turning an AC into a heat pump, so there is little additional cost. Then the CCHP has a couple more valves than that. Going from AC to heat pump shouldn't be more than a couple hundred bucks, and then to cold climate should only be a couple hundred more.

The CCHP tend to to be dual splits. While the equipment may be cheap the labor to install it isn't. Most people aren't going to install their own dual split and run the electrical to it.

I was doing a bit of shopping today (still haven't decided if I'm going to go with a dual split or keep the stock rear A/C in the ambulancd)

12,000 BTU, 23 SEER, 10 HSPF, 2.1 COP at 5F, works down to -13F and costs $1,049.

https://www.amazon.com/Optima-Invert...=sr_1_3?sr=8-3

Originally Posted by redpoint5

With economies of scale, it'd probably be cheaper to just manufacture all to be CCHP with no option for inefficient systems. I need to disrupt this corrupted industry by starting my own business.

Buyers want options - good, better, best. While making all your heat pumps super efficient you will save a bit through economy of scale the other guy is going to be offering people low efficiency units for 30 - 40% less. A good number of people - maybe the majority will buy the cheapest option even though it costs them a lot more over the life of the product.


(Hybrid cars are an excellent example. There is no reason economically for the regular Corolla to exist. That $1,850 purchase premium for the hybrid pays back 4 x over the life of the vehicle in fuel savings alone)

[redpoint5]

Originally Posted by JSH

Buyers want options - good, better, best. While making all your heat pumps super efficient you will save a bit through economy of scale the other guy is going to be offering people low efficiency units for 30 - 40% less. A good number of people - maybe the majority will buy the cheapest option even though it costs them a lot more over the life of the product.

Is the actual cost to manufacture high efficiency really 30-40% more is my question?

I'm always skeptical that a thing that costs twice as much costs twice as much to make, especially when all the same components are necessary for function. The thing I always think of is a bicycle. You have to have 100% of the components to make a functional bicycle, so instead of making a crappy one for $100, why does a really good one cost $5,000? How does one get from $100 to $5,000 bending metal in roughly the same shape?

Add bicycles to the list of corrupted industries I'm going to dominate (beds are next).

[Piotrsko]

Heat pumps you pay for freon type used and packaging the components. Sometimes really high efficiency scroll compressors. Freon type determines how cold it will still extract heat..they were all within say 10-20% of each other. Other part of the install is how much you are paying for your dealer choice. That is half to 2/3 of the install price.

Mine could be bought for $5,000, came with enough freon to run 40ft of line. Has really odd flares, requires special inspection from county permits. The remaining $15,000 was moving all the ducts to a new transfer box and disassembly to get parts under the house then reassemble. concrete access hole is 14x 14 x24

Bicycle might be a bad choice as there are hundreds of choices to make for options and skill of maker getting it just right. Yes there ought to be not much change between a Schwinn and a Huffy, and those prices are similar. Both were a fraction of the bike my son rides. They measured everything, there's not much adjustable and although I am approximately the same size, his bike is uncomfortable as heck for me to ride but he does 100 mile trips

[Isaac Zachary]

Originally Posted by JSH

The idea of saving with a heat pump in your case would need to be a hybrid approach. One idea would be to use the NG heater when the temperature is below 20F and the heat pump when it is above. Use each where they are most efficient. The crossover point would depend on the efficiency for each heating source and your cost for a therm of NG and the cost of a kWh. (What do you pay for those)

You can figure out how much NG you are using for cooking and hot water by looking at your bill in June, July, August when you aren't using your heat. (I do the same thing for electricity but I use April and September when I'm not using heat or A/C)

The other big factor is how warm do you keep your home. That has a huge effect on the cost of heating. Considering you turn off the heat completely at night when it is -20F outside and say heating a whole house is a waste I suspect you are doing just the bare minimum to keep the pipes from freezing.

Originally Posted by JSH

Yes, they can (mine does) but I don't see Isaac paying thousands for a Cold Climate Heat Pump. I was talking about him adding a small window unit for less the $1,000 that would provide A/C in the summer and cheaper heating in shoulder season.

Also providing 100% of BTUs at 0 F doesn't mean it makes financial sense to use a heat pump when he has a furnace.

Well, now I'm looking at all sorts of options and don't know quite what to do.

You see, my 53-year-old furnace died yesterday. The heat exchanger cracked and filled the house up with an odd chemical smell. I don't see the point in trying to fix a 53-year-old heat exchanger. I found the heat exchanger part number, but apparently they are no longer manufactured or in stock anywhere.

I can't find a furnace that will work that I can install myself, unless it's electric of some sort. I guess my only option is to hire a company to come install a new unit.

There is a new Colorado law that goes into effect on the 1st day of 2026 (in less than a week) that all gas furnaces must be ultra low NOx. That's why I can't find one that will work. Nothing is Colorado compliant. I guess I could try to get one that meets the current standard on Monday, but that's not a lot of time to go get one, and I'm not sure where to get one.

I'm tempted to install a ~25,000 BTU 240V 30A heat pump furnace replacement, but that won't work under -15 °F. It's been a calm winter so far, but last year I remember getting to work one day and seeing it was still -36 °F at around 8:00 a.m.

I have no idea what a hybrid system would cost or if they even make hybrid systems for trailers.

Another thing, I also read that heat pumps aren't as efficient if you bump the heat up and down between awake-and-at-home times and asleep-or-not-at-home times like we've been told to do for so many years. Trying to figure out what would be most economical for when to use a heat pump and when to use a gas furnace is a bit hard to figure out, as it seems Saturdays are about the only day that it make sense to have a heat pump running all day at the same temp. Otherwise it's either not really working (sleeping at night, or night is too cold) or it's working too much (waking up and heating home). Or I could just leave it at the same temp all the time, but wouldn't that be less efficient overall (unless we mean 45 °F all the time and a cold and angry marriage?).

Any ideas? What would be best to replace this cracked furance?

[redpoint5]

Describe your old furnace so we know what options are available.

[Isaac Zachary]

Originally Posted by redpoint5

Describe your old furnace so we know what options are available.

Thank you! Thank you!

The old one:

• Old and stinky.
• About 76" tall, 22" or 23" deep and 19.5" wide
• Stands up in hallway interior wall and pulls air in from hallway
• Natural gas
• Downflow heat exchanger
• 50,000 BTU output
• 62,500 BTU input
• 8.5" output duct on bottom
• Currently single chimney out the top (likely will need to be converted to double pipe "inlet-outlet" system)

The new one:

• Must meet ultra-low-NOx levels at 14ng/J (not "low-NOx" at 40ng/J) unless I can buy it before Thrusday
• 240V, up to possibly 40A could be a possibility for heat pump.
• Must work at 7,700 ft
• Must be mobile home rated
• AC option would be rather worthless

[Isaac Zachary]

It looks like it's going to be $5,000 to $7,000 installed from what I'm researching...

And that's just a natural gas furnace, not a hybrid system with a heat pump.

[JSH]

$5,000 to $7,000 sounds about right for a new NG furnace. My parents just replaced theirs and it was about $10,000 installed for a 97% efficient furnace for their 1000 sq ft home

You would likely spend a similar amount for a heat pump that would go in the same space.

How large are the temperature swings in your home. You said you turn off the heat at night - how cold does it get. What is the temp you heat your home to during the day when you are there?

Heat pumps can vary temperature fine but they are slower to heat up a cold room than a gas furnace because for a ducted system a furnace puts out air at 150F to 160F while a heat pump is 105 - 115F

My heat pump is set on a program:

• Mon - Thur 62F at (9 pm), warm to 67 in the morning (4:30 am), drop to 65F at 6:00am, heat to 72F at 3:00 pm, then 65F at 5 pm.
• Friday we are home so it is 69 from 6 am to 3 pm
• Sat / Sunday it is 69 from 6am to 9 pm (no peak electrical rates on weekends)

We are shifting our temperature a max of 10 F which works fine. If you are heating from 45F in the morning to 65 - 70F and then turning off the heat again when you go to work then on again at night when you are home I doubt a heat pump will work well for you.

With a heat pump as a primary heat source you would also need back-up heat for at night when the outside temp drops below the heat pump rating. (assuming you heat at night) A small electric heater would do that.

DIY you would likely need to go with a 36,000 BTU ductless in your kitchen / living room and then a smaller 24,000 BTU unit on the other end of the house in the master bedroom. That would likely cost as much as a furnace or singled ducted heat pump

Realistically just replacing the furnace is likely your best bet in your climate.

[JSH]

I'm having the opposite issue right now. I'm in North Carolina for work and staying in a hotel for 3 weeks. My neighbors are trying to roast me.

I have the A/C on to keep the room at 69F. However, at night when the temperature drops below 40F the A/C stops working. By 5 am the temperature in my room is 75F.