Aircon vs dehumidifier in this weather

[David]

I realise that an aircon unit will both cool the air and remove humidity.

However in this weather I am finding the relative humidity (75%+) to be more of an issue than the actual temperature.

Dry heat is reportedly much less unbearable (more bearable) than wet heat.

So would a dehumidifier (cheaper than aircon and also useful in winter) be a sensible option?

Noting that you would have to more or less seal the room.

Just speculating because the weather is scheduled to break tomorrow in most places.

Cheers

Dave R

[Theo]

Won't a dehumidifier just heat the room further? It has no connection to the outside, and it takes in an electricity supply. That electricity is being converted to heat, and it has nowhere to go but the room.

Normally a dehumidifier is used somewhere cold and the extra heat is a welcome bonus as it makes the room more comfortable and pushes the room away from the dew point.

Whether it makes sense to reduce the RH so you can sweat more efficiently, and use the dehumidifier to collect the evaporated sweat in a tank, meanwhile *raising* the room temperature, I couldn't say.

Theo

[Tim+]

An air to air heat pump air conditioner will also be useful in winter as they can also heat with a COP of 4 (1kW in for 4 kW of heat output).

Tim

[Bob Eager]

I haven't tried it out. My aircon (bought a few weeks ago [1]) will do fan, dehmidify, cool, and heat. Haven't tried it on dehumidify yet.

The door of the room is a bit leaky and it's a tilt swivel window, but I have a Heath Robinson arrangement that works OK.

THe calculators say abput 9,000 BTU/hr for the room, but with the PCs etc. I got a 12,000 BTU/hr one. It is OK, but only manages to reduce the temperature by a certain number of degrees (which is understandable).

Today it is chasing the increasing heat but it does make the room quite tolerable.

[1] The delivery was a chapter of accidents. The first two arrived broken (they weigh 30kg) and had to be repacked and sent back; the second one wasn't even plugged in as it had a shattered base. The cycle time for each was about 10 days, plus 6 days while I initially worked out the window sealing.

[Bob Eager]

Yup, mine allegedly does that.

[David Wade]

I doubt it. Why do we Brits have this obsession with avoiding the proper solution. I see lots of folks in Spain buying and then selling portable AC units ...... because they are noisy, don't work well etc. So if portable AC doesn't work well is a simple de-humidifier going to help.

My wife was very unconvinced about my AC units. Yes they were more expensive than a de-humidifier, but they are effective at both heating and cooling. Now we have them she loves them.

Not sure why you would need to seal the room....

Then might be a good time to invest ready for use as auxiliary heating in the autumn...

Dave W

[David]

I was trying to work out in my head if the increased comfort due to raised temperature and lower humidity might make the room more comfortable.

It would at least make sweating easier.

£50 entry level might be worth a punt.

If I was going for air conditioning I would be looking at a split unit with the heat exchanger outside which is a whole lot more money.

Cheers

Dave R

[David]

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To avoid trying to dehumidify the whole world. With air conditioning you tend to keep the room closed so the cool air stays in one place.

You don't usually run air conditioning with all the windows and doors open.

Cheers

Dave R

[Pamela]

A nuisance I get with a portable aircon unit is sealing the window so the exhaust air can vent out but the warm air can't get in. It can take a bit of setting up.

[Pamela]

My portable aircon unit can be made to run only as a dehumidifier but the improvement in comfort is minimal.

I get the impression when a dehumidifier runs, it also dries out items in the room such as carpet, upholstery, perhaps even the walls to some extent. This would mean it's less effective at drying only the air.

[David Wade]

To me sealing the room involves addition actions over and above closing the doors and widows, which one should do anyway if the outside temp is higher than inside

In Spain I have a room with open stairs, a large hatch to the kitchen, and a open door, and the AC still seems reasonable effective.

Dave W

[Tim+]

But would avoid throwing away £50. ;-)

Given the way the climate seems to be changing and the fact that with a COP of 4 it’ll be cheaper to run than a gas heater it seemed a no brainer to us to make the investment.

Tim

[Jeff Layman]

I use a piece of 4mm polycarbonate sheet about 600 x 400mm. It has a

150mm round pipe connector screwed to it to take the a/c vent hose. To "fix" it to the window I use 8 pieces of self-adhesive Velcro stuck on the sheet and PVC frame, four at the corners and the other four equally spaced at the long sides. It takes only a few seconds to fix up or remove. As it's a close fit to the frame, hot air can't get in.

[Theo]

One problem is that UK a/c installers aren't exactly ten a penny, so they charge inflated prices. In hot countries a/c installers are as common as plumbers, and installing an a/c unit is about as complicated as fitting a bath.

Hopefully with non F-gas refrigerants becoming more popular it will lower the bar and more people will take on the task, without needing to take the

1000 pound training course.

Theo

[David Wade]

Perhaps I was lucky...

Dave

[Bob Eager]

That's right. My solution involves half a Dacron skirt for a tilt swivel, the blanking plate used for up-and-down windows, and a piece of 75x75mm wood held in place with a G-cramp.

[me9]

My aircon cools the house slightly, but takes out gallons of moisture, making it comfortable

My old fridge type de-humidifier took out a smaller amount of moisture but heated the air enough to make it uncomfortable.

My current dessicant dehumidifier is not quite as bad as teh fridge type but not effective in hot weather.

The last two years I've almost managed to keep the environment comfortable by night ventilation, minimising the electric bill.

[me9]

Mine's a two box one, outside and inside units. connected by small pipes which can go through a small opening.

It's long in the tooth and the gas is no longer available, I can't find a suitable portable relacement without an astronomic price tag.

[me9]

Also the latent heat from condensing the vapour adds to the heat. Does COP apply?

[me9]

IME it does the opposite.