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Astrokev

Warm room ventilation

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Hi Folks

For those following my build thread, you will know that I'm currently insulating and lining the inside of my warm room. As with everything else with my build, it's going slowly, but will hopefully be fully lined out by next weekend.

At the moment, the warm room design is such that there will be no vents or gaps in the walls, apart from the door to the outside, and the door to the scope room. With me cooked up inside with both doors shut while my scope does it's thing, I will be breathing out water vapour, and I'm becoming concerned that this may cause problems if the moisture has no where to go, and may condense on the walls and surfaces when I close up the observatory and the room cools down. I'm beginning to wonder whether I should fit some sort of ventilation.

Should I be concerned? Adding vents is fairly straight forward but this will allow heat to escape and makes me wonder why I'm bothering to insulate the room.

I'd be grateful if others can advise and maybe show examples of what you've done to deal with this.

Many thanks

Kev

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I guess my warm room was never that well sealed 😁  Nowadays it's just the power supply room and equipment and tool store.

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13 hours ago, paul mc c said:

You have one at each end for air flow ?

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I'm interested in this one !

I've just fully insulated my little shed to use as a warm room too.

Previously this shed was a sealed condensation box with marked temperature fluctuations, so I’ve replaced the windows with shiplap to block out daylight (to hopefully reduce temperature fluctuations) and put in two small passive vents (one high and one low) to allow airflow.

I've put the vents in thinking it must be the sensible thing to reduce condensation risk, but I am also wondering whether it will just lead to heat loss when I’m in there, even though I've insulated from top to bottom? I'm hoping as this shed is so small the heat loss won't be too much of an issue, but time will tell, once I’ve hooked up the electrics I’ll give it a go !

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Thanks for replies so far. I see  there's another thread just started asking similar questions.

I currently don't have any ventilation vents in the warm room, so am thinking of putting a few in. What would be the best - one at the top and another at the bottom I presume. And would it be best to have the top and bottom vents on different walls to encourage air movement across the room?

Retrospectively adding vents shouldn't be too difficult, but I need to see what's available to find a design that will ensure no rain can get in.

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My warm room vents to the scope room which has excellent ventilation!  Gaps everywhere but they are such that they don't let rain in whichever direction its coming from.  Well, at least that is the intention - I have some work to do regarding weatherproofing...

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These are from screwfix but easily available at most diy outlets. They have a fly mesh in them and the vanes point down, I ran a bead of mastic along the inside top edge before screwing down so water can't get behind. Think they were a pound each? In the torrential rain a while back these little things didn't let a single drop in so do the job brilliantly. You could get bigger ones and ones that open and close. I only have them in my dome side as I don't need ventilation in my warm room 👍

51.jpg

Edited by LeeRich

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Come in this size too.

https://www.screwfix.com/p/map-vent-fixed-louvre-vent-with-flyscreen-white-229-x-229mm/8886d

As you have cavity walls you could make a simple open ended box and have a vent inside and out, wouldnt particularly achieve anything except look prettier on the inside. I would have two low down on the side of the prevailing wind and then two more higher up near the top on the opposite side 🤔 if poss. Means cutting holes now but this is where planning plays a big part, but it's an easy fix.

Edited by LeeRich

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13 minutes ago, LeeRich said:

Come in this size too.

https://www.screwfix.com/p/map-vent-fixed-louvre-vent-with-flyscreen-white-229-x-229mm/8886d

As you have cavity walls you could make a simple open ended box and have a vent inside and out, wouldnt paticulally achieve anything except look prettier on the inside. I would have two low down on the side of the prevailing wind and then two more higher up near the top on the opposite side 🤔 if poss. Means cutting holes now but this is where planning plays a big part, but it's an easy fix.

Thanks for your thoughts. My obsy was thoroughly designed and planned out in Sketchup and everything has gone perfectly to plan (so far). Excluding vents was not an oversight, I just didn't want any, but ideas evolve! Still don't know whether I need them. Whatever I do should be simple enough - the cavity wall shouldn't present a problem. 

Last resort (if condensation proves to be a problem) could be to get a dehumidifier, which I know you're an advocate of. 

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That's the problem, you just can't predict if your building will suffer or not so In hindsight it's probably a good thing you didn't plan for vents but as we have mentioned, it's an easy fix. Whichever route you take with vents if indeed you do I am sure it will look in keeping with your already spectacular looking project 👍

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As with all things in this hobby it isn't black and white 🙄

Ventilation serves more than one purpose and, if you are planning to sit in the mostly sealed warm room for long periods, it is a good idea to add a small amount of ventilation to mitigate the inevitable rise in CO2 levels.  If it is well insulated and has a breathable vapour barrier, as I think yours does, then condensation shouldn't be an issue at all as the cool moist air from the outside will condense on the vapour barrier, that's what it's for.

In the scope room area ventilation is fine, but it definitely isn't the panacea of condensation control; your location also needs to be considered.  If you live in a pretty damp area (high levels of rainfall) or close to the sea for example, you will often have quite damp air.  When the outside Rh is high, such as on a misty day with low clouds, then the moisture is in the air air and this moisture doesn't stop at a vent.  This is precisely why barn find classic cars still rust, even in well ventilated barns, as the damp is in the air.  Victoria tells me she knows when Rh levels are high as her hair "gets big" 😀

Unfortunately it isn't only condensation we are fighting.

Personally I want my warm room to be warm (clue is in the name :smile:), so have a panel heater on a stat and a small, high level, sliding panel vent which I can open when I am in there and close when I'm finished.  The gaps under the doors are sufficient low level in a room of this size with limited occupancy.  There is only a small amount of heat loss through the vent, so it really isn't noticeable.

My scope room is insulated, but I also have a dehumidifier to help remove the moisture following an imaging session and to keep the Rh at a level that I choose (this is 50% for me).  It doesn't come on much, but when it is a damp and misty day, with high external Rh it does come on. 

Your kit is very expensive, buying and running a dehumidifier, in comparison, isn't.  

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In my observatory there is no door to the "warm room" section - yet it does keep the chill out and cuts any wind down to more or less zero.  Once I'm gone the air can circulate throughout the building - there are plenty of gaps around the sliding roof and I have never noticed any condensation inside the observatory.  I suggest you simply leave the warm room door open when you are not using it.

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1 hour ago, RayD said:

.... In the scope room area ventilation is fine, but it definitely isn't the panacea of condensation control; your location also needs to be considered.  If you live in a pretty damp area (high levels of rainfall) or close to the sea for example, you will often have quite damp air.  When the outside Rh is high, such as on a misty day with low clouds, then the moisture is in the air air and this moisture doesn't stop at a vent. .... 

This is exactly what happens in my outside buildings.  If the weather here (near the coast) changes quickly from cold and dry to warm and damp and I enter a building or open a window or a vent I can see all the cold surfaces cloud over instantly.  The larger the gradients the worse the condensation.   The better the insulation the steeper the gradient the more dramatic the effect gets, the best insulated unheated room (just like a fridge) can hold a low internal temperature for several days after prolonged frosty weather.   

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Yeah I have no ventilation in my warm room, but it is fully lined with vapour barrier. Just open the door when you finish and let it vent through your well-ventilated scope room. @Gina if you vent in to the scope room, you'll inevitably get turbulence as the warm air escapes and this could actually affect your images. If I ever have my warm-room door open while focusing, the difference is huge - the image goes all blurry!

Edited by Shibby

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I haven't found any problems of that sort.  The warm room isn't all that warm anyway and only gets used as an equipment and storage room nowadays as I do remote imaging from my living room indoors.

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