Heat ventilation recovery unit on boat

[Restoration man]

spotted these units on eBay recently and apparently there very good at stopping condensation and mould etc in houses , has anyone tried one in a boat ? Ok I know there 240v so could only run when on shore power etc , but I was thinking more for when the boat is left in the winter, instead of using a dehumidifier, the device could be permanently fitted even you could even buy pipe in the bilges to help keep them dry , and left on 24/7 they use very little electric , should be less fire hazard than a dehumidifier , ,if you had a inverter /solar power this could also Potentially used when away from shore power, there are other types around some that claim to use very little electric, and some have the heat exchanger made plastic so that might be better idea if your on the coast , thought I would ask the question before I buy one to try ?

 

[vas]

assuming it's a heat exchanger with a fan to support shifting air about, it would be reasonably easy to replace the 240V motor for a 12 or 24 one I guess.
bit expensive though...

 

[V1701]

On an empty (unheated) boat in winter I think effectively what you'd have would be an expensive, complex (ducting to and from all cabins?) ventilation system, i.e. no or very little heat benefit as no heat in the boat to start with...

 

[[70521]]

I can't see that improving my ventilated boat.

 

[Restoration man]

On an empty (unheated) boat in winter I think effectively what you'd have would be an expensive, complex (ducting to and from all cabins?) ventilation system, i.e. no or very little heat benefit as no heat in the boat to start with...

My thoughts are it will help keep my boat dryer during the winter no need for a dehumidifier,I understand that if it’s not warmer in the boat than outside the air returning won’t have any extra heat , but just moving air in boat does help keep them nice and dry , that can’t be a bad thing , and I’m sure the fan in this will cost less to run than a dehumidifier,
, Plus improved ventilation when I’m using the boat and I will benefit from the slightly pre heated air being ducted into the boat , win win in my eyes?

 

[Keith-i]

They are intended to extract warm air from a damp environment and transfer the heat to dry cool incoming air. Unless you are also heating the interior of the boat I’m not convinced there will be any appreciable difference in absolute humidity to make it worthwhile.

 

[ProDave]

Unless you are heating your boat (liveaboard?) in winter I can't see the benefit.

In houses, these allow you to make the building air tight and avoid heat loss by draughts, and instead supply a steady stream of fresh air and extracting stale air, and recovering the heat from the extracted air, thus keeping the building warm.

If the boat is unheated, you will achieve the same thing just with an extract fan at one end and drawing air in at the other so you have a through flow of air to keep it fresh.

 

[V1701]

My thoughts are it will help keep my boat dryer during the winter no need for a dehumidifier,I understand that if it’s not warmer in the boat than outside the air returning won’t have any extra heat , but just moving air in boat does help keep them nice and dry , that can’t be a bad thing , and I’m sure the fan in this will cost less to run than a dehumidifier,
, Plus improved ventilation when I’m using the boat and I will benefit from the slightly pre heated air being ducted into the boat , win win in my eyes?

Sure but the unit is £320, you'd have to buy all the pipework, would have to run it here there and everywhere to each cabin, presumably the inlet & outlet in each cabin would be best at opposite ends of the cabins not right next to each other. All that pipework would take up a lot of space in lockers, etc. it just doesn't seem worth the hassle & expense but each to their own...

 

[srm]

I find natural ventilation plus a low wattage tubular heater at the lowest point of the cabin sole has kept the boat dry and mould free with bedding etc on board for umpteen years in the north of Scotland. If electricity is expensive fit a timer. Much cheaper than the OP and less hassle than a dehumidifier that sensibly needs a hermetically sealed boat to avoid trying to dry the world's atmosphere.

 

[Kelpie]

Unless you are heating your boat (liveaboard?) in winter I can't see the benefit.

In houses, these allow you to make the building air tight and avoid heat loss by draughts, and instead supply a steady stream of fresh air and extracting stale air, and recovering the heat from the extracted air, thus keeping the building warm.

If the boat is unheated, you will achieve the same thing just with an extract fan at one end and drawing air in at the other so you have a through flow of air to keep it fresh.

Exactly.
This idea has some merit if you are living aboard in a cold/damp climate.

 

[gregcope]

I fitted a similar Mechanical Ventilation with Heat Recovery (MVHR) unit to the house. Its brilliant at keeping the house drier. Also filters air of pollen etc..

I can see the point if onboard and heating as condensation in a small space is an issue. If boat is just stored ventilate more would be an answer as the heat recovery will do very little.

You can get single room models that are probably better suited to a boat as these heat exchangers are based on volume (air changes and hence rate).

 

[V1701]

I fitted a similar Mechanical Ventilation with Heat Recovery (MVHR) unit to the house. Its brilliant at keeping the house drier. Also filters air of pollen etc..

I can see the point if onboard and heating as condensation in a small space is an issue. If boat is just stored ventilate more would be an answer as the heat recovery will do very little.

You can get single room models that are probably better suited to a boat as these heat exchangers are based on volume (air changes and hence rate).

Exactly, and if on board dehumidifiers are very effective at reducing condensation and hugely increase comfort. My wheelhouse in particular would be sodden without one and despite what some will have you believe you only need to close doors/vents/hatches, i.e. you do not need to hermetically seal your boat and they are not rendered useless because it isn't. A decent dessicant dehumidifier can easily cope with the relatively small amout of outside air that inevitably gets in to our boats. So to set that one at rest, whilst they are not going to be working at 100% efficiency you are not attempting to dehumidify the planet...

 

[penfold]

Total waste of time and money unless there are sources of damp(people, gas cookers, tumble driers etc) and a significant temp difference between inside and outside. Most boats are very poorly insulated so a heat recovery unit would be like the little dutch boy and a dyke with more holes than a colander.

 

[Restoration man]

Ok well it appears it was a stupid idea , it was worth the ask ,thanks to everyone who replied, and saved me some money on foolish idea,I will have to dream up something else stupid to waste my money on ???

 

[bedouin]

These are a mechanism to recover heat from the warm air inside a house so you can increase the ventilation without a corresponding increase in the heating bill. If used on an unheated boat they will be no better than a fan and less effective than a dehumidifier