Hi, this is my first post here. I 'm currently in the planning stages of revamping the heating system in my 1600 sq ft home. It's a ranch on a slab currently heated by an oil burning baseboard system. Additionally a Spacepak central air system is installed in the attic with high velocity duct work distributing the air. I have a Waterford Ashling woodstove that is installed almost directly under the Spacepak. I currently run the fan only option while burning and this definitely helps distribute the heat of the stove. My question is about the feasibility of installing a hot water coil in the stove and hooking it up to a hydronic coil in the airhandler. Spacepak makes a unit that will handle 60000 btu, and from what I can gather my woodstove puts out about the same. I've done a bit of standard HVAC work so I understand the basic logistics of a system such as this , ie need for expansion, thermal storage, etc. I'm not looking to be able to satisfy all my heating needs with this project, but I'm interested in the efficiency of such a system, and whether the cost (about $2000-$2500 with me doing all labor) is justified. I can get all the wood I need for free. Any advice especially from someone who has done something similar to this is most welcome! TIA!
Is This Worth It?
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I would think that your money would be better spent on putting in a gasification wood boiler that operates at a higher efficiency and can heat the house through the existing baseboard system. An Eko 25 or Biomass 25 would be a good size for your house. If you want to put in heat storage, you could go up in size a bit and add some convenience of not having to fire it as often. I would suggest eventually putting storage in anyway, as you can then use the boiler in the shoulder seasons and for DHW in the summer. Your above mentioned plan might work... but a gasifier would allow you to go completely fossil fuel free!
He's not going to be able to do a wood boiler for $2500. The problem I see is pulling so much heat out of a firebox that you'd kill the burn. Is that an EPA stove? Maybe run a coil to a storage tank, then pull off of that.
Run the coil for stove to a tank and have a 3 speed pump tied to a sensor tied to the output, so as the stove temp goes up and down the pump could pull more or less heat. then use your baseboard to push the btus through a manifold to your current boiler. That seems more controllable then just a coil pushing heat when/where you don't need it.
Run the coil for stove to a tank and have a 3 speed pump tied to a sensor tied to the output, so as the stove temp goes up and down the pump could pull more or less heat. then use your baseboard to push the btus through a manifold to your current boiler. That seems more controllable then just a coil pushing heat when/where you don't need it.
btuser said:
I wasn't implying you could get a wood boiler for $2500. I was simply saying that if you are going to put money into something like this, you should go all the way. The cheapest way to do something is to do it right the first time!
Agreed, but I'm a budget-kinda guy. If you've got $2,000 to something or nothing it's worth to do something that may go towards what you really want. $2 grand for the header, circulators, and the take off to a heat exchanger for the stove, and then if he gets the bug and goes for the gasifier its a couple of unions and 2 shut-off valves. Presto! I'd rather rund a circulator than an air handler. I think the baseboards would handle the fluxuation of the water temps much easier. Going into a tank would give you the luxury of using a mixing valve to control the output of the rads.
Thanks for the quick replies! If I was planning on staying in the house for 15 or 20 yrs the wood gasification would definitely be an option, but I'm thinking more like 5 yrs, and I think going all wood would kill resellabilty in my suburban area. I'd be happy with recovering the cost of the upgrade over the 5 yrs I plan to be here. My cost to heat with oil will end up around $1600 this season, and assuming that the cost of oil remains stable I'd need to cut my usage by about 25% to make it pay. I guess I need to know if this is feasible. The system I'm considering is basically a coil in the firebox connected to a circ pump feeding water into the cold water inlet on an electric water heater (or possibly 2 in series) and out the hot to the air handler with an expansion tank installed inline. Naturally a t&p blowoff will be vented safely away. I was planning on winding the return line from the airhandler around 2' or so of the smoke pipe before it reconnects to the coil to extract some exhaust heat. Since the coil in the airhandler can handle approx the total btu out put of the stove I'm not overly concerned with overheating anything, but the 3 speed pump setup is a definite. The stove is not an EPA unit and I realize that I'll have to burn quicker and hotter. Any further thoughts?
I'd just remind you a non-epa stove is lucky to get 60%, and wood aint that cheap. why not just go to the boiler and use hydronics, which is better than warm air at transfering heat?
For the same money as your project and considering the payback period you require, you could get a big stove like the BK King and be done. I have no problem heating more space in a colder climate with it. Easy to operate, long burn times, no risk in project, qualifies for tax credit, etc. A nice bonus is you will use a lot less wood than with your current stove. Free or not, processing and burning wood takes time.
SolarAndWood said:
As much as I love fun diy projects and hydronics, I think this is the best idea I've heard so far. Especially if you are only planning on being there 5 years. Resellability wise, people would probably like a nice handsome stove over a cobbled together unit with diy hydronic heat attached.
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