Dehumidifier recommendations for hot tub in a wooden enclosure?

[Privateer]

Hi,

First of all, I'm a newbie so apologizes if I've posted in the wrong place! 

We just had our hot tub, which is a Jacuzzi 480, for a few weeks. It is out in the garden sitting on a new reinforced base of concrete. We have a cedar wooden structure built over it which measures 4 x 4 metres base, and 2 metres at the rear and 2.5 metres at the front, which is approximately 36 cubic metres.

When the hot tub is not in use, the cover is left covering the hot tub.

Having noticed condensation on the glass of the wooden structure, I put a humidity meter by the hot tub and found that the relative humidity was at times over 90%. The windows don't always have condensation on them.

Would I be able to use a normal house dehumidifier to control condensation? If so are there any that you can recommend?

What specifications should I look for?

Is it possible to have a hose pipe to feed from the dehumidifier to a bucket/tank/jar etc (but still inside the wooden structure) to allow the system to work for days without having to empty the internal tank of the dehumidifier?

Many thanks,

[av8r]

I'd engage an HVAC engineer to determine what you need for this.  I doubt a home dehumidifier will be able to keep up with the load.  I think you're going to need a large fan drawing air out of the structure and an intake opening large enough to allow the fan to run efficiently.

Good luck.

[Tman122]

I'd engage an HVAC engineer to determine what you need for this.  I doubt a home dehumidifier will be able to keep up with the load.  I think you're going to need a large fan drawing air out of the structure and an opening large enough to allow the fan to run efficiently.

Good luck.

Yea. Is this a heated structure? Ventilation may be all that's required.

[amy2421]

I'd engage an HVAC engineer to determine what you need for this.  I doubt a home dehumidifier will be able to keep up with the load.  I think you're going to need a large fan drawing air out of the structure and an opening large enough to allow the fan to run efficiently.

This was kind of what I was thinking too... in an indoor residential application we would recommend a heat recovery ventilator, to exchange the air and ventilate the space.

[Privateer]

Hi av8r, Tman122, and amy2421,

Many thanks for your replies.

The cedar wood structure is not heated at the moment. Currently we only have the 32 amp power supply for the hot tub itself, however we're hoping to soon have power sockets and lights, with the possibility of network, telephone, etc. as the structure is next door the garage which is wired for everything.

I'll have a word with the suppliers of the hot tub and the cedar wood structure to see if they know of a good HVAC (nb for my own reference: heating, ventilation, and air conditioning) engineer in our area.

Regards,

[kasandrich]

Heat recovery sounds like a good idea!

My Son is a building management systems engineer, he has promised me an extractor with a Humidity sensor, so when the humidity hits a pre set threshold the extractor will cut in, but adding heat recovery sounds like a good idea.

I am sure he could set up to monitor internal and external temperatures plus humidity and if the humidity is high switch on extraction and if the outside temp is below a certain point, add heat recovery

[Vinny]

I truly think you're overthinking it. If the air outside the structure is less humid then inside then a ventilation fan is all you need along with openings for air flow; I would install either a humidistat or a timer. Install the fan high and have the openings low and you should be fine. My bathroom gets a lot more humidity from hot showers then a hot tub throws out and a 110 CFM fan keeps it pretty clear during showers and once the shower is over and the door is opened whatever moisture is left is eliminated pretty quickly; I typically have the fan running for another 15 minutes after I'm done.

If you are concerned about the humidity when you'r not using the tub definitely use the humidistat and whenever the moisture gets above a certain level it will click on. Just be aware that during high humidity periods that the humidistat won't differentiate between hot tub humidity and outside humidity that gets into the building.