Talk Morgan Forums Community The Malvern Arms Garage heating

The car does not need to be kept warm but you do when pottering in there. So no reason for 24 hour heating, or however long you keep the house central heating on.

On the other hand the car is sensibly kept dry so occasional while you work heating using a calor heater for example isnt the best idea. In stead you might use a fan heater or even a wood burner. As a further alternative, Lidl do an excellent line in insulated boiler suits that are easy to work in.

If I were rebuilding my own garage, the one thing I would install would be a urinal. Its incredible how often I start a job only to want to pee. Plus a sink of course.

The present garage has a fan heater I can plug in. Also an oil filled rad if needed. The garage in the house we are moving to has a rad on the central heating system. I will probably leave it but move it to a better place, out of the way. I have only used heating in cold spells. The V8 chucks out quite a bit of heat when cooling down!

I'm a bit mystified by this. Are you saying your dehumidifier collects more water when you artificially heat your garage?

Relative humidity will decrease as you heat the air, not increase. And RH will increase as the temperature goes down. Absolute humidity, if it's a sealed space, will not change but the ability of the moisture to condense, and thus settle and cause corrosion, will be reduced as temperature rises in comparison to the outside air.

There could be an effect from air pressure here i.e. warm air is less dense so as the air in your garage is heated the cooler denser air from outside tries to get in. But I don't think this would be significant.

The reason why the air is so dry in an airliner is that air with an already low humidity (at high altitude) is drawn in and then heated, reducing RH to the extent of drying our skin and making eyes sore.

Signed, mystified non-meteorologist.

You are correct. The amount of water in the air in the garage is constant and independant of temperature. Its likely to be the same in gm/ cu metre as the water content outside unless the garage is effectively sealed or has just received a wet car from washing. Thermodynamics ensures that. Damp air will migrate into or out of the garage to equalise.

However, most all chemical processes are time and temperature dependant. Rusting is a chemical process in that sense so in theory the car will rust ever so slightly faster in a warm garage than in a cold one. Maybe 3 or 4% faster for every 10C?

If you are worried about that issue, and you shouldnt be since modern coatings protect steel from rusting very effectively, then you can help by using a de-humidifier in the garage.

Family car lives outside in rain and snow and with salted roads but doesnt rust, and that cost way less than a Morgan.

Howard I'd assumed that reducing relative humidity would reduce corrosion whether through raising the temperature in the body of air or by removing moisture with a de-humidifier.

But you're right and searching around the google universe reveals that yes, higher temps will accelerate corrosion. I haven't yet found anyone citing an ideal ratio of temp to RH but a number of sources give below 60% as a desirable RH for hindering corrosion. This extract below is taken from the Journal of Materials in Civil Engineering and copyright is the American Society of Civil Engineers... Of course going too low in RH is going to have unwanted effects as well, such as drying out timber and fabrics.

Abstract

It was found from field surveys that suspension bridge cables were under severe corrosion environments due to the water and high temperature inside the cable. Corrosion environments depended on the wire positions inside the cables. Wires were found to be continuously wet at the side, wet at night and dry during the day on the top, highly humid at the center, and soaked in the water at the bottom. Accelerated corrosion tests using galvanized steel wires showed that the side wires were most severely corroded, the bottom wires were also significantly corroded, but the upper and the center wires were rarely corroded. These phenomena agreed with the actual cable corrosion. The tests also showed that galvanized steel wires did not corrode when they were kept with a relative humidity below 60%, but became corrosive with the higher relative humidity. Larger amounts of sodium chloride increased corrosion considerably. The corrosion rate also exponentially increased with temperature. It was predicted that the zinc layer would be consumed within 10 years when wires were kept in the wet or soaked environments, 34 years with a relative humidity of 100%, and 211 years with a relative humidity below 60%. - See more at: http://ascelibrary.org/doi/abs/10.1061/(ASCE)0899-1561(2004)16:1(1)#sthash.zzr3mwqc.dpuf

Relative humidity is just the percentage of moisture in the air compared to the maximum that it can hold at that temperature. Given that the maximum goes up with air temperature, so the same amount of moisture gives decreasing relative humidity numbers.

My guess, and it is only a guess, is that data on a bridge isnt very relevant to a car in a garage. With the bridge you will get condensation at times when the bridge structure cools overnight, something that I have never had happen in my garage. And guessing further, II suspect that water droplets on some steel will have it rust quicker that moisture in the air.

All educated guesswork at best!

I have just finished sealing my garage door up from drafts (as was fed up of it filling up with neighbours leaves) I have just replaced our house dehumidifier as old one was reluctant to start (handy for drying out a wet OES) I then repaired the old dehumidifier (motor cap had given up the ghost) it now resides in the garage with the mog where if I Park a wet mog in the no longer draughty self airing garage it will get shot of the excess moisture. The plus side is that the dehumidifier as part of its operation produces heat and is enough to take the chill out of the garage.

What's a chill?

First garage I ever worked in had a Salamander heater. This contraption has probably been banned by the Health & Safety and if not by most insurance companies.

It ran, when it ran on a mixture of diesel and waste oil. It needed careful filling - no more than half full or the oil used to boil, catch fire and spew across the office floor!

Lighting it defined bravery......and you soon learned not to be the first in the workshop on a winters morning!

Arwyn

Well according to our rellies down under anything below 25°C