Portable air con/heat pumps

iannewp

Anyone know anything portable air con/heat pumps/dehumidifiers? They seem to be available at £500 -1k, compared to heat pumps at many thousands. 

Thinking about improving conditions in my damp basement , (Has access to an outside wall for vent), not interested in using as air con, just heat and dehumidifier. 

How do they compare? Comparable efficiency to heat pumps, given the much cheaper purchase price?

grumbler

iannewp said:

Thinking about improving conditions in my damp basement , (Has access to an outside wall for vent), not interested in using as air con, just heat and dehumidifier. 

What do you want to achieve? Any electric dehumidifier (except desiccant ones) is essentially a heat pump extracting moisture and heating a room. So is any portable aircon without a vent. And if you want to heat the basement, not cool it, you don't need a vent. A portable aircon will work like a powerful dehumdifier and heat the air at the same time.

FaceHead

I will watch this thread, as I will shortly be in the market for one for the garden office I'm building. Not only does a heat pump mean heating will be probably twice (only) as efficient as a panel heater, you can run it in reverse have summer AC. Seems like a win-win. As I am building the think, I have the luxury of being able to put a pipe through the wall. 

My expectation is that their coefficient of performance will be even poorer than an air source (which is poorer than a ground source) - but when the alternative is a panel heater, for me it's a no brainier. 

I've seen new at £300 (Portable Air Conditioner Heater Dehumidifier 9300 BTU with Remote | eBay).I might get one second hand through - probably a recognised brand for less than this new one. 

Clearly 9300BTU is pretty puny, but it's sufficient for a single office room. 

iannewp

Thanks for all the replies, very useful information.

What am I trying to achieve?

I converted the basement, during lockdown, from an unusable damp space with a leaky drain, into a workshop.

So, I'd like to bring humidity down to 60% from 70+. To bring the temp up to 18 when I'm in there. Central heating not an option. 

It occurred to me that in heating mode, these units might also provide a background heat for the floors above, but being much cheaper than electric heaters

Many thanks

grumbler

iannewp said:

So, I'd like to bring humidity down to 60% from 70+. To bring the temp up to 18 when I'm in there.

Electric dehumidifier, say 500W, - heats air like any 500W electric heater + dehumidifies it + produces about 0.7kWh of heat per every litre of collected water.

Split system aircon (or heat pump heater) in heating mode - heats air inside more efficiently than an simple electric heater, but doesn't dehumidify it. In cooling mode - cools and dehumidifies air inside.

Portable aircon connected to a vent - the same as a split system in cooling mode, but pumps air out. If not connected to a vent, works similarly to a powerful dehumidifier.

FreeBear

iannewp said: I converted the basement, during lockdown, from an unusable damp space with a leaky drain, into a workshop.

So, I'd like to bring humidity down to 60% from 70+. To bring the temp up to 18 when I'm in there. Central heating not an option.

How did you convert this basement ?

Anything underground (either fully, or partially) is going to be cool and damp. Tanking the floor & walls will stop most of the damp, but without a decent level of insulation all round, it is going to be difficult to heat effectively.

When I've used an Ebac dehumidifier, I've found the temperature in that room is get nice & toasty without any additional heating. But this was in a well insulated room on the first floor.

waqasahmed

FreeBear said:

iannewp said: I converted the basement, during lockdown, from an unusable damp space with a leaky drain, into a workshop.

So, I'd like to bring humidity down to 60% from 70+. To bring the temp up to 18 when I'm in there. Central heating not an option.

How did you convert this basement ?

Anything underground (either fully, or partially) is going to be cool and damp. Tanking the floor & walls will stop most of the damp, but without a decent level of insulation all round, it is going to be difficult to heat effectively.

When I've used an Ebac dehumidifier, I've found the temperature in that room is get nice & toasty without any additional heating. But this was in a well insulated room on the first floor.

What power dehumidifier and what size of room?

I was also looking at a portable heat pump heater, largely as a way of cheaper electric heating within the house, without first buying an expensive ASHP

markin

The cheapest split a/c heatpumps will be more efficient and get the noise out the house/ shed/office.

Some cheap portables units just use an electric ELIMENT for the heating mode, I think they may need 2 pipes to do real heating from the air.

waqasahmed

C Irumbler said:

iannewp said:

So, I'd like to bring humidity down to 60% from 70+. To bring the temp up to 18 when I'm in there.

Electric dehumidifier, say 500W, - heats air like any 500W electric heater + dehumidifies it + produces about 0.7kWh of heat per every litre of collected water.

Split system aircon (or heat pump heater) in heating mode - heats air inside more efficiently than an simple electric heater, but doesn't dehumidify it. In cooling mode - cools and dehumidifies air inside.

Portable aircon connected to a vent - the same as a split system in cooling mode, but pumps air out. If not connected to a vent, works similarly to a powerful dehumidifier.

So around 140% efficient? Surely an air con in reverse would be normally around 300% efficient? 

grumbler

waqasahmed said:

C Irumbler said:

iannewp said:

So, I'd like to bring humidity down to 60% from 70+. To bring the temp up to 18 when I'm in there.

Electric dehumidifier, say 500W, - heats air like any 500W electric heater + dehumidifies it + produces about 0.7kWh of heat per every litre of collected water.

Split system aircon (or heat pump heater) in heating mode - heats air inside more efficiently than an simple electric heater, but doesn't dehumidify it. In cooling mode - cools and dehumidifies air inside.

Portable aircon connected to a vent - the same as a split system in cooling mode, but pumps air out. If not connected to a vent, works similarly to a powerful dehumidifier.

So around 140% efficient? Surely an air con in reverse would be normally around 300% efficient? 

Split system aircon in reverse mode is 300% efficient because it pumps heat from outdoors to indoors (thus cooling something outside).

Electric dehumidifier both cools the room and heats it (more than cools). If the air is absolutely dry, it's 100% efficient as heater. More efficient if the air is humid. I don't understand how you came to 140% figure. I don't know whether at very high humidity it can be more efficient than a split system aircon. Even if it can, it's purpose is to bring the humidity down and in this case its efficiency as a heater will drop.

GValue

Iv'e been looking at these too @iannewp and I wonder how long they would need to be used for heating and cooling to payback the investment of £500 for a room of 36 sqm with an outside portal, using an Airflex 15W with Wifi? 
https://www.appliancesdirect.co.uk/p/airflex15w/electriq-airflex15w?