Who’s pumped for a heat pump—-> this guy!

[NorthernMac]

Hey folks,


I’m looking for a heat pump system for my 30’ cutter, ideally mounting it in the engine room, which is going to be getting a good bit of attention, what would you guys recommend for a boat that spends a good bit of time at shore, but also 30% off shore, a good central low profile/clean install/light weight and hopefully not chinese made system, mostly used in the slip to heat/cool and keep dry the entire boat?

Temp range would be 30f to 110f OAT, New England to Florida and the Bahamas

[rbk]

Typical Heat pumps will require between 10-15 amps to run so it’ll be dockside and genny dependant. Second will be space required for both the condenser and head unit, I would assume a split (heat/AC). Pound for pound you’re probably best off installing a diesel heater and a separate self contained AC unit when needed. Mounting a condenser in your engine room is a bad idea as well. If you’re thinking about utilizing engine heat you can install a drop in red dot type heater.

[a64pilot]

Anything to put on a 30’ boat will be a “package” unit, those need to have cabin air returned to them to recirculate the air, so engine rooms etc is out, they go behind a settee or some similar place, I have one under our bunk for example.

But the above post was correct, they are a Marina thing only, a Honda can run one, if it’s small enough or had a soft start etc.
Personally I would only consider one that functions as both a heater and an air conditioner, why not? It’s not bigger or heavier, just has a reversing valve is all.

If you want to extract engine heat, look into a bus heater, they can be plumbed into the same circuit as the water heater, but of course require the engine to be running.

[NorthernMac]

Originally Posted by a64pilot

Anything to put on a 30’ boat will be a “package” unit, those need to have cabin air returned to them to recirculate the air, so engine rooms etc is out, they go behind a settee or some similar place, I have one under our bunk for example.

But the above post was correct, they are a Marina thing only, a Honda can run one, if it’s small enough or had a soft start etc.
Personally I would only consider one that functions as both a heater and an air conditioner, why not? It’s not bigger or heavier, just has a reversing valve is all.

If you want to extract engine heat, look into a bus heater, they can be plumbed into the same circuit as the water heater, but of course require the engine to be running.

Reverse would be great and what I’d be looking at, I was only looking to install in the engine room because I have dead space back there and would like to keep all compressors, including the fridge I want, back there, or would that not work with ducting?

Maybe something like this but not made in china?




https://www.westmarine.com/buy/webas...59?recordNum=7

[rbk]

Problem with the engine room is heat. All condensing units to dissipate heat ie good air flow of which engine rooms tend to lack. You could direct a blower to the units to help but if you’re running your engine you will greatly impact your refer (while running) and then your AC for several hours once at dock/anchor. Best to keep both units in separate well vented cabinets. What is the BTU of the above unit? My guess is 6-8k? If so that may just (borderline) do the job, depends on the boat, insulation and personal preference.

[NorthernMac]

Thanks

6k, and would mostly be used (like 85%) while at dock with the engine off

[Sailmonkey]

Originally Posted by NorthernMac

Reverse would be great and what I’d be looking at, I was only looking to install in the engine room because I have dead space back there and would like to keep all compressors, including the fridge I want, back there, or would that not work with ducting?

Maybe something like this but not made in china?




https://www.westmarine.com/buy/webas...59?recordNum=7

You don’t want to put that in the engine space, it’ll inject engine smell into the whole boat.

Like a64 said, these are installed in the cabin. I put ours under the V-berth and ducted it to the salon.

[a64pilot]

That one is actually not bad, takes about 5 amps to run it.
I’ve had one under our bed for I guess maybe four years now? Anyway it’s quiet so we never hear it, just the airflow.
However I don’t believe it’s enough for a 30’ boat, I’d think that will take a 12K.
It’s barely enough for our Stateroom and head, especially in Summer heat.
Good luck finding one not made in China. I’d suspect even if you find one US made, it’s actually assembled from parts made in China.

China is the next Japan, wait and see, remember when Japanese meant cheap junk?

[Sailmonkey]

Originally Posted by a64pilot

However I don’t believe it’s enough for a 30’ boat, I’d think that will take a 12K.
It’s barely enough for our Stateroom

We use the 6k on our 32’ boat. It’s relief during the day, and more than adequate at night. Depends on if you need it for more than a good nights sleep. But it fits in a smaller space than the 12k unit.

[a64pilot]

Originally Posted by Sailmonkey

We use the 6k on our 32’ boat. It’s relief during the day, and more than adequate at night. Depends on if you need it for more than a good nights sleep. But it fits in a smaller space than the 12k unit.

In 110F weather?
That’s what he is asking for. Size wise you’ll have to look that up, but I don’t think it’s that much different, it’s certainly not twice as big.

[a64pilot]

For the Webasto’s this link gives sizes of units etc.
https://www.webasto-comfort.com/file...um_Bi_Fold.pdf

The Webasto’s are an “economy” solution, but near as I can tell they work fine I’ve had two for four years or so and so far trouble free, plus. A complete install is not inexpensive with seacocks, thru hulls, water pumps and ducting etc.

[Dockhead]

Originally Posted by a64pilot

For the Webasto’s this link gives sizes of units etc.
https://www.webasto-comfort.com/file...um_Bi_Fold.pdf

The Webastos are an “economy” solution, but near as I can tell they work fine I’ve had two for four years or so and so far trouble free, plus. A complete install is not inexpensive with seacocks, thru hulls, water pumps and ducting etc.

We had Cruiseair on the previous boat (now Webasto?). It worked great and was trouble free for about 20 years.


It's a brilliant solution for heat when on shore power. At least when the water temperature is reasonable, it uses a small fraction of the power which would be needed for electrical resistance heat.


We had no generator so could not use the system EXCEPT on shore power, but we never felt we needed AC on the hook, so this was fine. For cold weather you will want some kind of diesel heat for when you are not on shore power.


Pay attention to your shore power connectors once you have relatively big electrical consumers like this on board. Recent discussion on here about that which you find by searching.

[Sailmonkey]

Originally Posted by a64pilot

In 110F weather?
That’s what he is asking for. Size wise you’ll have to look that up, but I don’t think it’s that much different, it’s certainly not twice as big.

In the heat of August in Texas it keeps the cabin dry and cooler than outside. Once the sun loading disappears it’s quite adequate. For us the goal isn’t to attempt to keep the boat as cool as a house inside, only to make it comfortable to sleep aboard when in an airless marina.

If the goal of the OP is to maintain 72 degrees all day, the 12k may not even be large enough, but possibly too large for comfortable humidity at night.

[NorthernMac]

Originally Posted by Sailmonkey

In the heat of August in Texas it keeps the cabin dry and cooler than outside. Once the sun loading disappears it’s quite adequate. For us the goal isn’t to attempt to keep the boat as cool as a house inside, only to make it comfortable to sleep aboard when in an airless marina.

If the goal of the OP is to maintain 72 degrees all day, the 12k may not even be large enough, but possibly too large for comfortable humidity at night.

That’s pretty much it, south Florida keep the boat comfortable enough for me and a small Australian Shepherd, don’t need to lock into 72 24/7, but I don’t want the boat to turn into a jungle or make me want to get a hotel room lol

[Sailmonkey]

Originally Posted by NorthernMac

That’s pretty much it, south Florida keep the boat comfortable enough for me and a small Australian Shepherd, don’t need to lock into 72 24/7, but I don’t want the boat to turn into a jungle or make me want to get a hotel room lol

This is the real problem, imho, with large air conditioners on small boats. You may be able to maintain your set point during the heat of the day, but at night the short cycling of the compressor means that you’re living in a cool rainforest.