Portable air con for surplus

https://www.boards.ie/discussion/comment/120670120#Comment_120670120

Fair point with benefit of a temp air vent into the attic. Bear in mind with using an attic door (with a new large hole in it), you don’t wanna breathe in rock wool insulation fibers. Or minimise it.

I considered a giant fan in the attic door instead of air con. They do that in The States, or did back in the day pre air con. Forces all the hot air from house into the attic close to bedtime. Dirt cheap to run as it’s just a fan. They really work – fans are mad powerful and the size of the attic door so pushes a huge volume into it and pulls in cools night time air in the process (from windows open in the house).

But then I realised you don’t wanna breathe in rock wool insulation fibers. So that huge fan would ‘disturb’ the insulation which would come back through the door. And we’re breathe it for the whole duration we used the fan (the summer). I expect it would be somewhat similar with an aircon pipe. The dust crap from the attic would have to settle in that when it’s powered off. And maybe that’s minor and fine for people. Not suggesting people don’t consider it, just think if it causes other issue. That said I’d likely do it myself for the few hot nights it’s hard to sleep.

When our solar installer was here in the attic, he’s a really good mask to filter the air he breathed. He said it’s like he’s been smoking if he works in an attic without the mask, he just won’t do it. Tinternet tells me ‘Breathing in rock wool fibers can potentially be harmful to your health. When rock wool is disturbed or handled improperly, it can release small airborne fibers into the air. These fibers, if inhaled, can irritate the respiratory system and potentially cause health issues.’ - likely makes sense if you ever spent time moving stuff in an attic.

Would be mould in the insulation too from leaks at times, or from condensation from water pipes in winter maybe. Again, don’t wanna breathe that stuff in daily if you can.

the_amazing_raisin

Somewhat OT, but I remember reading a review of an indoor heat pump water heater with an integrated tank.

I was very confused about the reviewer saying that had the exhaust going into the attic. I was wondering why you'd be dumping cold air into the attic in winter, then I realised it was in California where winter is a bedtime story to scare children 😂

[Deleted User]

A good fan is probably more than sufficient. I can't imagine too many houses needing air con in Ireland.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120671341#Comment_120671341

The problem is these new A3 rated houses are pretty excellent at retaining heat. Great in winter when it's freezing out, not so ideal in summer

I'm also pretty sure the insulation has a radiant heat barrier (tin foil) on the inside, but not the outside. So it stops radiant heat escaping, but allows solar gains from the sun. Again, great for winter, not great in a heatwave since it effectively warms the house up

I agree that airflow helps a lot, had a few fans last summer which kept things tolerable in the heatwave

The main issue there is you need to keep the fans going through the night otherwise the heat builds up again. Also if the outside temp is 27C then you can't really magic it much cooler with a fan. Might knock a few celcius off but it'll still be extremely warm at night

I guess the idea with an air conditioner is to "store" cool air in the house during the day and stop the house becoming overheated while the sun is out

I don't think it'll work miracles however because you'd have to cool the entire house, otherwise you'll have warm air coming in from other rooms

graememk

I agree none of this is a need though, we're having good weather now but the evenings are still chilly and any heat build up in the day is lost through opening of windows.

Fans only counteract the skin effect and remove the boundary layer of insulating air, knock a few c off with air con, and then have a fan to circulate the air about too

I'll still be closing curtains etc when it gets really hot to try and keep the heat out when the next heat wave comes... I'm already in shorts in this weather. 😆

mustang68

I installed a mini-split in the garden office, I got it for the efficient heating (SEER 6.2), but it's free cooling in the summer (the office can get quite warm).

I made a few phone calls to get quotes in Ireland, but most were commercial installers or wanted stupid amounts of money to do it, after a bit of research I opted to do it myself.

You can get a kit that comes with everything you need, including (this is the important part) pre vacuumed lines - if you don't get these you'll need to have someone out to pull a vacuum, or get a pump to do it yourself (the units all come with refrigerant preloaded). All in the kit was about 1000 shipped on a pallet. Mitsubishi 2,5kw. It needed a hole though the wall for the lines, drain and power connector - about 5cm - that was the hardest part.

It's really quiet and can run at a very low power, highly recommended.

https://www.boards.ie/discussion/comment/120682024#Comment_120682024

Fair play. I’d deffo be interested in that. Could have it tipping away heating on low wattage from solar in winter. Would you consider yourself an average DIYer, or a ninja? Wondering in terms of the level of work to install it.

Could u pop in the link for the model you got?

Is there any way to see the pressure of the gas in the lines now it’s installed? Afaik if there’s a leak it’s hard to know without an actual pressure gauge (similar to the one on a gas boiler for water pressure). And performance goes to crap, but it’s hard to tell.

mustang68

https://www.boards.ie/discussion/comment/120682563#Comment_120682563

I'm an average DIYer, was nervous going into it, but the reality is that that when you go outside Ireland to warmer climates you see mini-splits everywhere as DIY installs, so they are designed to be easy install. In the US there is a brand called Mr Cool, that uses similar connections, lots of youtube videos on how to do them that got me looking at this as an option. Hardest part was putting a hole in the wall, the drain must be facing down so you have to keep that in mind

This was the kit I got on ebay, you can specify mounts and the length of connections between the units, came with instructions. Unit works well, but the Mitsubishi App isn't going to win awards for innovation.

There isn't a pressure gauge, but there are a bunch of connectors that I'm sure you could attach to if needs be. I'll be treating it like my car AC, if the performance drops then I'll see what the issue is.

When running it tends to run low and slow, only taking a 200Ws or so, I've only had it a few months so your mileage may vary.

https://www.boards.ie/discussion/comment/120682794#Comment_120682794

can i ask you - can you have the heat pump on the back of the house and run the pipes through the attic and down to unit on the front of the house? we have a 4 bed semi in dublin and it does get warm upstairs.. last summer was over 28 degrees inside and that was with black out blinds closed in the rooms, and basins of ice sitting in front of a pretty large honeywell fan..

mustang68

https://www.boards.ie/discussion/comment/120687020#Comment_120687020

You can have the refrigerant pipes run any direction, but the drain pipe cannot run up - the ice buildup on the inside unit melts and the water has to drain (it's not pumped), if the pipe runs uphill the unit will leak. The drain pipe doesn't have to go back to the outside unit, it just needs a drain somewhere.

poker--addict

this DIY option is extremely interesting. Presumably there is some DIY units with a few splits. I would ideally want 3 or 4.

https://www.boards.ie/discussion/comment/120689763#Comment_120689763

Think SD_dracula posted one before that could take up to 3 indoor units / splits. Can't recall if that was DIY or not. With a few splits the pipework becomes longer with more connections that you would need to make yourself to fit your house. And there's pressurised gas in it, so more chance of leaks. Might have max distances between splits back to the outdoor unit on DIY units. So the DIY element gets harder I guess.

But I'm deffo in the camp of not ruling out a DIY myself. If it came down to a costly home heatpump V a cheaper but lower performing COP on an air to air mini splits... Well, it's worth some number crunching

People say the downside is it can actually feel colder as the air is blowing over you. That cools us down of course (even when hot air). But I reckon I could live with that, just mind where you fit it so not over your head when sitting

con747

https://www.boards.ie/discussion/comment/120689763#Comment_120689763

These were posted before. https://www.buyitdirect.ie/p/multi-split-27000-btu-smartapp-wifi-inverter-wall-air-conditioner-with-3x-9000-btu-indoor-units-to-a-single-outdoor-unit-iqool-3ms9k9k9k##reviews

poker--addict

That one certainly says it requires an engineer.

Stealthirl

I got a portable one a few years ago as im a night worker and sleep in a southern facing room, regularly seen +25c on hotter days and +30 on rare occasions.

I made up a plug for the window with 10mm PIR cut an angle on one side and velcro sticky tape on the frame to hold it in place. It's not airtight, but was the best i could come up with. I have a 125mm hole in that for the extract, and the flexi hose is an insulated one to reduce thermal gains. I don't mind the noise as it drowns out lawnmowers, kids, dogs etc.

If noise of the unit would be an issue, the mini split is perfect. I might get on eventually, but at the time they were 2 or 3 times the price of the portable unit. Normally it draws about 9-1100w when cooling and about 500w when it's just the fan

right last night was another reminder i need to do something about this... re the refrigerant in the unit linked on ebay.. that all comes pre filled?

https://www.boards.ie/discussion/comment/120687020#Comment_120687020

As far as I recall the pre-filled units can't be extended without having an AC engineer visit (or you obtain a vacuum pump and refrigerant) - you can only work with the pipe which is supplied as the pressure is already set by virtue of the preset length. So yes you can do what you describe, but also factor in the losses over a long pipe run as these will add up.

[Deleted User]

https://www.boards.ie/discussion/comment/120671389#Comment_120671389

I don't think this is the case. I've done a full retrofit of my home which would have been cold in winter and too hot in the summer. Now it's great in winter and so far, even with the rear being south facing it's not uncomfortable, open the windows first thing then the house stays at a nice temp. It could be the mechanical ventilation at play but in general the insulation should prevent massive swings in temp.

SD_DRACULA

https://www.boards.ie/discussion/comment/120689444#Comment_120689444

You can get tiny pumps for this so you can go up too, they usually sit in the elbow trunking of the indoor cassette, so they can be run via the attic

DownByTheGarden

I got a vision 3.1. Great for AC and even better for heating in the winter. Just bore a couple of holes and mount it on an outside wall in the room you want heated/cooled. Ours was the kitchen. I was thinking of getting another one for heating the sitting room in the winter too because they are dirt cheap to run.

https://www.boards.ie/discussion/comment/120708231#Comment_120708231

It's all about the "thermal mass". You have an inner-leaf block wall of 100mm thickness insulated in the cavity and it heats up to 24 degrees in the midday sun - that block wall will release that heat slowly over the night back into the room (as it can't radiate it into the cavity due to the insulation) and you'll feel it all night. Only by preventing that wall from taking on that thermal load will you manage to have a cool room in the evening and night.

In my bedroom with three external walls I installed 50mm of insulated plasterboard on the North facing block wall. That keeps it from being a thermal store in the Summer and stops the cold coming off it in the Winter. I consider it a good move.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120708231#Comment_120708231

Maybe, we've no mechanical ventilation and our house is definitely suffering when there isn't a breeze to circulate air

EDIT: I should probably say the occupants are suffering, the building itself is fine

https://www.boards.ie/discussion/comment/120708428#Comment_120708428

Good to know on the insulation. Thermal mass is the exact issue we have with our red brick house - basks in the sun and roasts us at night. Was the insulating on the internal wall?

https://www.boards.ie/discussion/comment/120709160#Comment_120709160

Yes, internal wall insulated plasterboard. Easier to heat in the Winter and less heat off it in the Summer. The South and E/W facing walls weren't treated the same way, they were left exposed so that we had some thermal mass, but the windows within them were upgraded from double to triple glazed.

https://www.boards.ie/discussion/comment/120709279#Comment_120709279

Wow, wouldn't have realised that internal insulation would make much difference. Cheers, helps me a lot to know it can

https://www.boards.ie/discussion/comment/120709778#Comment_120709778

It can - and there are trade-off's. 👍️

still contemplating options re cooling.. chatted to a friend who had a ceiling fan light installed and he's happy out with its cooling effect.. apparently a great job?

graememk

offically have a heatpump in the house (screwfix, 12000btu.. about 3.5kw ish) uses about 1.5kw

V noisey as expected, (its being vented out a vent I have in the cupboard originally planned for an external air for the fire but never used)

Moved to the bedroom last night and it was able to precool it from 23/24c to 18 before we shut it off for the night.

yeah thats the approach i used before while in the states one summer.. used to over cool during the day and switch off the units before bedtime so the noise wasnt an issue.