Large Car Garage - heating?

sudo911

Hi Guys,

I'm building a large garage to store the cars and trying to figure out the best way to heat it.

It'll be 18x13m with 4m at the eves... 60mm insulation on the roof panels, side sheeting and roller doors. A friend put in an A/C type unit in his garage and says it costs about €5 a day to heat and to keep the air circulating (although I know one wont be enough for this size). I've seen others put in gas heating, but with no circulation and other ideas talking about a heat pump etc.

Either way, I'm clueless as to the best way to go here and wanted to get advice if anyone has already been down this road...

Ideally I just want to keep it around 14/15degs in the garage to avoid rust forming (chrome bumpers etc) and the premature perishing of rubbers etc.

p.s. Admin move to a more appropriate section if reqd, but figured this forum might be the best!

antodeco

Im hoping to do something similar in the future. However, for the last 11 years Ive been storing my cars in an unheated garage, and never had any issue. Coldest it ever got was 6 degrees and that was in the very cold weather a few weeks ago. In fact today, despite it being 8 degrees outside, the garage is currently at 12 degrees. It is well insulated, with roller doors, but Id say the roof on mine could be better insulated.

hoodie6029

Would putting the cars in the likes of a Carcoon be a better option for you given the size of the space?

drunkmonkey

Shouldn't 60mm insulation be enough if everything else is correct in the shed build, ventelation etc. I've 40mm insulated and it seems to do the job there's no damp or condesnsation in there, haven't felt the need to heat it.

sudo911

https://www.boards.ie/discussion/comment/121761463#Comment_121761463

I was wondering if I needed to do anything at all, but a bit of heat in it would be great - especially if I end up sticking an aul couch in there with a beer fridge and TV! But you've had no issue with rust forming then over the 11yrs?

sudo911

https://www.boards.ie/discussion/comment/121761570#Comment_121761570

I was looking at that before but wont have room for them (amount of cars) and its a bit of a PITA taking them in/out the whole time. I'd prefer them all on show. Whole point of this new build was to get it right to avoid things like the Carcoons.

sudo911

https://www.boards.ie/discussion/comment/121761681#Comment_121761681

Possibly... I guess I could just live with it for a year and see what happens and retrofit it later. Dont have any ventilation at present in the plans - what did you do? Electrical fan or just normal vent?

listermint

Air tightness and controlled ventilation is the order of the day.

For periodic heating if your out there I'd just get a small diesel space heater tbh, cheap to run and cheap to buy.

hoodie6029

It would be a big investement but what about a solar installation on the roof to feed a battery? Use that battery to power infrared panels or some other electric heat source. If you’re planning on using it as a leisure space too, it’d make it very comfortable place.

Big upfront cost but you never have to worry about bills on the garage again and feed it back to the grid when you don’t need it.

drunkmonkey

https://www.boards.ie/discussion/comment/121762011#Comment_121762011

I didn't put any vents in, went with one of those thermostore sheds from adman, 6.1m x 12.3m x2.4m.

There's 2 classics in there, one had already a small bit of rust but I've been tidying it up and it definitely hasn't increased.

If I was doing it again I'd have went a little higher so I could stack 2 cars. Happy with it besides that, it's never got too cold in there and everything is nice and dry.

sudo911

https://www.boards.ie/discussion/comment/121762018#Comment_121762018

What is the best solution for the controlled ventilation?

sudo911

https://www.boards.ie/discussion/comment/121762048#Comment_121762048

That was the original plan, but as I'm putting solar on the main house (a good bit away from the garage) - apparently my installer said I cannot have two solar deployments at the house and needed to go through some complex application with ESB Networks to get a 2nd installation. I was thinking exactly that though, solar panels with battery feeding the heat source.

Clo-Clo

https://www.boards.ie/discussion/comment/121762379#Comment_121762379

You have to fill in a form and submit to ESB. It's not that complex and I got the form off them before

If you get approved from recollection they will charge you 1k for the ability to have a system larger than the standard

The issue here is the solar panels won't work during the winter to generate enough heat and you will end up just burning electricity to keep the place warm, especially if not insulated to a high enough level.

hoodie6029

https://www.boards.ie/discussion/comment/121762610#Comment_121762610

With a big enough array and topping the battery up from cheap overnight electricity, it shouldn’t cost too much to run over winter.

Sounds like the OP is looking for a simpler solution anyway.

listermint

https://www.boards.ie/discussion/comment/121762366#Comment_121762366

Humidity controlled units, you can get mechanical ones for low money they open on humidity, or you can go fancier and get electronic ones with heat recovery in them.

Ventilation is key for any environment where you want to maintain some level of air quality.

thomas 123

https://www.boards.ie/discussion/comment/121762006#Comment_121762006

Build a room inside it with its own heating and extrnal grade windows and doors , could put a big window in it looking out at cars.

The biggest relationship between rust and storing cars in a garage is damp. Lots of people foolishly park a damp car into a garage with poor ventilation and think they are doing a car a great service when in reality you be better leaving it out in the rain because at least then you will have a breeze at some stage to dry it off, especially underneath and in the hidden areas like wheel arches. If you park a car in a garage wet and if there is no ventilation then damp doesn’t clear, having a heated garage will only go so far with this.

a dehumidifier with a humidity sensor is always a good recommendation. Buy a good quality industrial one (read reviews from the perspective of garage owners), buy the right one and they can be very reasonable in terms of cost to use and durability and they need a big water tank / external hose as the amount of water they pull from the air is huge.

a car carcon as also suggested is a good recommendation, no point getting a big garage to an ideal conditions if you only need these conditions for 10% of the area.

sudo911

https://www.boards.ie/discussion/comment/121763177#Comment_121763177

That makes total sense and aligns with what a lot of folk have said re: airflow and damp. So in summary a good industrial demudifier, controlled ventilation and the adhoc-heat source for when I'm working in the garage sounds like the ideal cost-effective solution.

I wasnt knocking the Carcoon, just I'm limited by space and really wanted to avoid that for the number of cars. I've 18 cars I plan to store in this garage so space is a premium. I plan to install 6 cars directly over another 6 using four-post parking lifts. The vintage of the cars ranges from 30's, 40's, 50's all the way up to modern cars etc.

I must have a look and see what controlled ventilation fans I can install for the unit that listermint mentioned. Is there a ratio here to calculate what I need, or will one be sufficient? 🤔

Casati

Make sure you insulate the floor too, ideally with another 60mm. If you had the budget build it airtight and install a heat recovery ventilation system.

A heat pump or electric rad powered by solar sounds good until you get three week of rain in the winter, personally I’d go with south facing roof windows to maximise solar gain and oil central heating that is linked to a stat to fire up only if it drops below 14 degrees. Such heating will cost v little to run. As other say, if you want a warm area man cave section this off with glazing and heat separately (ie have a separate zone with your heating).

sudo911

https://www.boards.ie/discussion/comment/121763646#Comment_121763646

Jeez... the options are endless 😁 Will be 100mm insulation in the floor. Hadnt thought of a heat recovery system - for whatever reason thought they were just for bathrooms. A quick bit of research online looks like it ticks the boxes in terms of air circulation, preventing damp and the provision of heat. I'm wondering what the cost of running such a system would be. Anyone used such a system?

listermint

https://www.boards.ie/discussion/comment/121764359#Comment_121764359

They're expensive. I have one it's for entire home.(centralised mechanical heat recovery ventilation)

You could get one of the all in 1 systems that have everything in just a wall unit.

De centralised heat recovery look it up.

You would have to examine your room scale and match a unit to it.