Using server room heat as additional house heat

Red Squirrel

I've been slowly planning out my server room as I am hoping to have the funds to build it by next summer. I want to be able to recycle the hot air to help heat the house. Now, I don't have enough servers to produce THAT much heat, but since it's constant, it may help.

I'm thinking of just ducting it to the furnace return duct. Is this a bad idea? Basically I would have a duct on the ceiling (since heat rises) and it would go down to my crawlspace (which would be in the server room) and to the return. picture to better understand the layout.

Another thought I had is add a small blower and push the air to the crawlspace under my garage, since I was told by the inspector this crawlspace needs heat. There's a 4800w heater in there now for that, so maybe the extra hot air would make it turn on less frequently.

Anyone else ever do any DIY hvac work like this, did it work? What kind of tools do I need to work with ducting anyway, never done it before, but want to learn.

Scuba_Dave

Myself I'd install the server setup in the crawlspace
They will stay cooler & heat will help the area without a fan
Or depending on the width of that opening build a rack system with an open back
Server heat would then enter the crawlspace

Red Squirrel

I'm planning to actually use the cool air to bring into the server room. Eventually that whole section will be closed off, but I'll have a fan or several fans sucking some of the air in the server room from the bottom (the bottom air will be the coldest).

Originally this was going to be my setup, but I'm debating on just going with a big custom shelf system, as most of my servers are towers anyway.





I thought of placing the servers directly in the crawlspace too, but prefer a full sized room for easier access. I'll probably run a sub panel there too later on, it would power the basement too once I finish it.

Flashheatingand

It would not hurt to vent the heat to the existing return. I don't think it's worth the effort to vent to the crawl space.

beenthere

In order for the furnace return duct to draw heat from your server room. The server room would need a supply from either the furnace. Or from another area served by the furnace.

A dryer hose, won't allow 9 120MM fans to move much air. It needs to be bigger.

Using just the crawlspace for cool air the the servers, may work. But, it may take more air flow then you realize.
What is the total wattage of your servers?

SELLC

I know a guy who is trying to do the same thing, but his heat is coming from 3 1000 watt high pressure soduim lights and balast.

Red Squirrel

Hmm why such lights?

The furnace actually feeds air to the crawlspace so the crawlspace does receive air from the furnace, and the crawlspace air will feed the serverroom, and the heat will rise and get sucked into the return. So while most of it will be passive think I'll be fine.

Also if I don't go with the return idea, I might use a booster fan instead of the pc fans.

I need to figure something out for summer though, maybe a damper and another pipe that goes outside but then I need to replace that air.

As for wattage I'm honestly not sure. At this point probably not more then 1kw and that's being generous. They actually don't put out that much heat but whatever heat they do put out, and future heat may as well be recycled.