Help Deciding on K6 or K8 Boiler

Hi,
New member but I have been reading a lot.

I moved into my house last April. The house is 200+ years old stone farm house with 18" thick walls, we are in the process of restoring it. Previous owner knocked down 2 of the 3 fireplaces. We installed a Blaze King princess in the remaining fireplace.

The current sq footage of living space is around 1500, that's not considering the 500 sq ft Attic that will be made into bedrooms, or the 385 sq ft room above the kitchen that we have no access to because the previous owner knocked down the steps.

We plan on adding an 2 story addition of around 1500 sq ft plus full size Attic.
The situation is a lot more complicated than described above.

I'm considering a k6 or k8 boiler. My dad has a k6 so I am familiar with that size. Gonna use cast on iron radiators. I live in southern Schuylkill county.

Thanks for anybody's input.

jrv8984,Welcome to the forum. If you enter your location into your profile,it makes it so much easier for those of us who can;t remember from day to day or page to page.With location in your profile ,we can just glance to the right of your post to see what part of the country you are trying to warm up. With location only in your first post,you will be asked multiple times as to where you are located. Your father uses the K6 to heat how many square feet of what condition house in what location ?If he is heating similar size & condition,you might be ok with the K6,but maybe you will be better with the K8. Will you be doing DHW as well,any plans for future heating of a garage or shop or....??The Keystoker experts will be along,likely with more questions.... we do seem to be a nosy bunch

If I remember correctly, another member has a similar home and situation. I'll try to find out and report back.

My dad is heating a 2400 sq ft (including finished Attic) 1860 brick farmhouse that we restored, the house is insulated.

I live at the base of the mountain range, so this time of year the sun doesn't even start peeking over the mountain until after 8am. My outside temps are always colder than any of the weather websites predict.

I may end up heating part of the garage or barn for our animals, but that would be years down the road, and only if I have the extra capacity. It's not really a deciding factor.

Welcome.

Before you pick out a boiler, you need to understand what kind of load you will be hooking up to it. Are the cast iron radiators already installed?

The house is 200+ years old stone farm house with 18" thick walls, we are in the process of restoring it.

Does the home still have uninsulated exterior walls? What restoration activities do you intend to complete before the heating system is installed?

Make sure that the installed radiation in each area is sufficient to cover the max heat loss you reasonably may experience, and size the boiler to cover the load produced by that radiation, a pickup factor to cover distribution system losses, an allowance for DHW requirements and any anticipated future loads (if needed), and a cushion to protect against the fact that the boiler won't always be operating at optimal efficiency.

Mike

I don't know the output of either unit,but in planning,go for the absolute worst case. In Jan. 1994,our region was hit with brutal low temps,we had -35* the one morning,if I recall correctly our high that day was like -8*,it was a very unusual brutally cold few days for this area. With my current heating systems in those temps,we would likely be short on heat. Plan now for that possibility,if the 6 is marginal,go with the 8.As coalnewbie says,"more overkill is better".

Can you tell us what your chimney plan is? You said you are down to the one fireplace. Are you going to remove the blaze king?

I would avoid direct vent, or power venting if at all possible. Seems like lots of problems getting those tuned lately, especially on a larger boiler like you're talking about. If you talk to Keystoker they won't sell a direct vent kit for the kb8, so that tells me a power vent isn't a great idea either.

I'll bet either boiler would heat your home, but i'm pretty sure I would get the extra BTU every time. Sounds like you're talking about 4000 sq ft , plus a basement?

If you are really committed to burning coal for your lifetime, I would personally make sure you had a masonry chimney of some kind dedicated to your unit.

I've got the following size radiators
2-25" tall, 7" deep, 24 section 6 tube
1-36" tall, 7" deep, 4 tube, 15 section
2-23" tall, 4.5" deep, 4 tube, 24 section
All in the garage.

Main house
Living room. 500sqft. w/40,000 BTU wood stove, 6 windows, 2 doors.
Bedroom A. 150sqft. 2 windows
Bedroom B 240 sqft. 5 windows
Attic 500sqft. Will become 2 bedrooms within the next 2 years

Kitchen addition 384 sqft with inaccessible 384 sqft room

Kitchen addition will be torn down and a larger addition will replace it. So total house size will probably end up around 4,000 sqft including attics

The wood stove is staying and will continue to be utilized.

I will be rebuilding one of the torn out chimneys if direct vent isn't an option. Does the k8 need a 9" dia chimney or would an 8" work. The chimbey will be around 36ft tall from the basement to 3ft above the roof peak.

Unfortunately this has to be an educated guessing game because so much is changing with the house.

I do want dhw from the stove as well, so that I don't need to use the propane hot water heater in the winter.

In addition to the other good information you are getting, you should get a good heat load calculation.

Here's one to get you started: http://www.loadcalc.net/

I recommend you print a pdf from each page to keep track of what you enter.

Once you know your heat load, you can start selecting boilers.

I have a KA6, but not fully loaded up yet, so can't speak to how it performs at the top end of its capacity.

Based on what I've read above, including what others with a similar house and heating load have bought, I would recommend the Keystoker KB-8 which is rated at 163k-net/192k-gross btu's.

I think it is important to distinguish heat loss from heating load. The program cited by CCW appears to estimate heat loss based on the characteristics of the structure. Heating load is an engineering property of the radiation attached to the boiler (i.e., the rate at which the radiation gives off BTU's from the boiler). You certainly can use heat loss estimates to determine the amount of radiation you want to have, but once you have that radiation installed, it determines the draw of BTU's from the boiler. Sizing the boiler according to the heat loss without accounting for installed radiation, pickup factor, DHW load, etc. as described in my previous post is a recipe for an underpowered system with a substantial risk of poor performance when the going gets tough.

Mike

Pacowy wrote:I think it is important to distinguish heat loss from heating load. The program cited by CCW appears to estimate heat loss based on the characteristics of the structure. Heating load is an engineering property of the radiation attached to the boiler (i.e., the rate at which the radiation gives off BTU's from the boiler). You certainly can use heat loss estimates to determine the amount of radiation you want to have, but once you have that radiation installed, it determines the draw of BTU's from the boiler. Sizing the boiler according to the heat loss without accounting for installed radiation, pickup factor, DHW load, etc. as described in my previous post is a recipe for an underpowered system with a substantial risk of poor performance when the going gets tough.

Mike

^^ What he said ^^

I used a different one, but don't have a link to it at the moment.

When I figured out mine, I used a calculator like above to get BTUs needed per room, then figured out how much baseboard it would take for each room, knowing its heating requirements and heat loss. Some rooms are more important, others less. Bedrooms need heat during the eve/night, but not much during the day, so they offset with a living room for example.

Then I attacked the most important areas and started a remodel to super-insulate those rooms. The "leftover" heat capacity will then be used for lesser spaces- like the basement- that must wait until the remodel to get any kind of decent heat in cold weather due to boiler sizing.

So yes, it is a bit more involved than just an online calculator for sure. But it's not a bad place to start.

Side note: When I started figuring out the heat loss for the different areas, I was SHOCKED to see how much WASTE some areas had We all know about drafty spaces, but the impact they have can be quite significant.

When I looked into alternative energies and ROI, it was interesting that INSULATION AND SEALING were the best investment by far. No matter what heating system you have, proper sealing and insulating saves you money quickly and constantly.

Maybe these experiences can help you make your decisions, too

CCW, thanks for the further description; I think it helps people to see how to use heat loss info. Sorry if I sounded nippy about that link. I start twitching when I see paths that may lead to underpowered systems.

Mike