Eberspacher:Rads or air

[Petercatterall]

Still thinking about heating my boat (and waiting for some larger Eberspachers on Ebay!)
I am looking for the blown air type but started thinking about the water heater type. Advantages could be:
Easier to fit water pipe than ducting
Less heat loss
Ability to connect up to engine for warm up
Ability to use engine water when engine running
I had thought of using a heater matrix in the main cabin (but noisy)
and ordinary rads elsewhere.
Just a (probably stupid) idea. Any thoughts experience welcome.
Regards

 

[trev]

I would recommend hot air. IMHO the fewer water pipes and glands running through the accommodation the better - and the ducting for the air blowers is not difficult to fit, you'll probably only need about three outlets for a forty foot boat - I have two in the saloon and one in the master cabin, if the doors are left open it heats the whole boat in no time, including the guest cabin in the stern.

 

[boatmike]

I agree with your conclusions and would add that the water heaters, because they are inherently simpler than air heaters are more reliable and less noisy. There is no problem routing waterpipes around the boat. Lot easier than all that ducting. You can use it to heat domestic water when you don't want anything else and because the water pump is less power hungry than a fan the electrical consumption is much less.
I have a 36ft cat and have had an air heater for a while but have just added a water heater to supply domestic hot water. Takes 30 minutes from stone cold to piping hot water and pulls no more than 3-4 amps. The air heater takes about 15 amps on start up and about 6 when running. If I were to start all over again I would have a water heater alone. Matrix heaters are a bit noisy though and because they have fans consume current too so if you can make do with radiators thats great if you have somewhere to put them. If you want to you can always use the engine to heat the system too when its running. All you need is a one way valve on the engine's water return hose to stop the eber from heating up the engine and wasting heat when it's not running.

 

[pvb]

Air, because...

Hot air is the easiest solution for most sailboats. Reason is that matrix heaters are noisy and consume current. Ordinary radiators are very difficult to mount in most boats - more importantly, they need to be very large in order to emit a reasonable amount of heat.

 

[alex_rogers]

Hot air has the significant advatage that it brings dry air from outside into the boat. This air gets dried further when it expands on being heated and this significantly reduces the condesation inside the boat. I find this completely removes the fug that develops when there are several people below and we are cooking.

 

[Petercatterall]

so... so far 3 favour hot air and 1 would go for water.
I still have a feeling that the water system is the most effective, but.....not simple and the fresh air idea is one that i had not thought of.
more thought needed... any advance on 3/1?

 

[nedmin]

I had hot air on my previous boat,found that you were either too hot or too cold,my latest one I had fitted with hot water(radiators) it is much better and also silent.You also get the benefit of hot water.Dont find condensation a problem. With the new push on plastic fittings shouldnt be too big a problem to fit.Mine is a Webasto and runs 7 small rads.If painted brown they are very inconspicuous.

 

[Peppermint]

Re: Rads

I met two people last season who'd changed from warm air to rads, on advice from other users, and neither regreted it. Warm air is noisy and uncomfortable by comparison. The air ducts are much larger than the pipework so bigger holes to be cut. So thats what people with rads think.

 

[pvb]

Radiator sizes...

If you want to avoid the high power consumption of fan-assisted matrix heaters (which are noisy as well), you're looking at ordinary radiators, as used in domestic intallations. For optimum efficiency, you need to use convector rads, which are typically 50mm thick. They need to be vertical. Let's assume you use rads which are 400mm high and 800mm wide (this is quite big in a boat). These rads will typically emit about 550watts, so you'd need about 6 of these in the main cabin to get the equivalent heat output of a 3kW air heater. Do you have space to put 6 of these? I certainly couldn't fit them in my 35-footer.

Also, the ease of installation argument for a radiator system isn't convincing - installation of either air ducting or water pipework is a relatively small job. What you should consider is the long-term practicality, appearance and convenience of either system.

 

[paulrossall]

I suspect that because you are on the West coast you will use heating more often than those of us that sail on the East coast. I moved from Manchester about 30 years ago to Nottinghamshire and was amazed at how much drier and warmer it was. I sail around Harwich and it is even drier and warmer than home. This does have a bearing on what type of heating to fit.
If I was a liveaboard I would seriously consider a water based heating system but would definately not use water otherwise. I have an Eberspacher 3DL (3 killowatt) and it just blows from the engine compartment up the cabin. It is more than adequate even for winter. I attempt to keep everything as simple as possible on the boat and would also think that any saving on running cost would be outweighed by the increased installation cost. IMHO. Paul

 

[cliff]

Have you considered "Ondol" type heating?

This is hot water but no radiators or matrices.

Just a long length of pvc pipe looped/coiled under the floor, inside lockers, under seats etc
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[philip_stevens]

I've got water heating on our Konsort Duo. One double panel single fin is in the forecabin, and the same size is fitted under the table in the main cabin. Both have thermostatic valves, and the system is time/temp controller. The system also heats the water in the calorifier.

During the past season, it proved to be more than adequate with the timer starting it up, so that we had a warm cabin and hot water, before we got up.

With the water heated system the Eber will modulate to keep running and keep the cabin temp to what you set it at.

As it is fitted inside the aft cockpit locker, there is very little noise from it when running. They all sound a bit like a jet aircraft from outside!!