New guy, lots of questions.

[leaddog]

Thanks leaddog. You kinda sound like my wife. "It's not that I don't think you can do it, you don't have time to do it."
You've been there and done it and it just doesn't always work like it is supposed to.
I'd looked into the HAHSA heater too....and read about people melting them down and such.

Patrick

Well I love to build things and I'm a scrounger and like to make do with things I find. I've made alot of mistakes and redone alot of thinks but enjoyed my journey. I'm very happy with the eko and the storage I have as I have done it cheaper than anyother way. Other people go other ways with other boilers. Alot of the decision comes down to how much you want and are able to do, space, time, resourses, codes, etc.
I bought alot of my stuff on ebay and at auctions. I bought 2 semi loads of propane tanks, Still have some to sell, bought LOTS of valves and pipe fittings, bought controls,and other stuff in quanities. I have a couple of BIG yardsales a year and resell alot of the stuff I don't use so it works out good for me.
But I don't think I will build another boiler.
Also after burying and redoing my underground piping 5 different times in all my expermenting I have finally got it right. Some times it doesn't pay to not do things right the first time.
leaddog

 

[pjcassidy]

Steve,
I'm working on these numbers....I just don't quite know where to go...

I have this from my electric Coop:

Date Meter # Reading Days Usage Monthly Charge
1/6/2010 56450982 61065 30 3630 $431.64
12/3/2009 56450982 57435 30 1851 $231.69
11/3/2009 56450982 55584 32 1672 $211.56
10/6/2009 56450982 53912 30 1435 $185.70
9/4/2009 56450982 52477 31 1600 $204.34
8/10/2009 56450982 50877 30 1355 $176.67
7/9/2009 56450982 49522 30 1639 $198.23
6/9/2009 56450982 47883 31 1412 $174.05
5/8/2009 56450982 46471 30 1845 $220.17
4/8/2009 56450982 44626 31 2345 $270.90
3/6/2009 56450982 42281 29 3233 $364.53
2/9/2009 56450982 39048 30 4319 $479.03
1/9/2009 56450982 34729 32 3883 $403.76

I've taken the "small" numbers, what I'm figuring is the bill minus heat (May-Oct) averages to 1519kwh

I've figured up the rest to 3016kwh
and with the two "wild cards" 5/9, 12/9 1845 and 1851
I took these two out and get 3483kwh
So can I say that my difference (or heating cost) is 1965kwh?
Or did I not use the right numbers here?

If I did, I'm getting $167 for the summer months, and $332 for winter months.
I don't know how much of that is for heating our HW.

I did talk to Jim at Garn today, he's sending me some information.

Patrick

 

[Gooserider]

Are you doing any AC in the summer? If not, I would tend to assume that your summer time bills are a pretty decent estimate for your "steady load" consumption, which would be lights, hot water, cooking, and so forth - this will go up a bit in the winter, as you will need a little more juice to heat the colder incoming water, and you'll use more lights cause it gets dark earlier, but those are both minor effects... Eyeballing the numbers, I'd say it looks like about 1400KWh / month steady load, going up to about 3600 during your peak months, or about 2200KWh for your cold weather heating load, and less than that for shoulder season...

This doesn't seem to inconsistent with your other bill numbers, where again I would suspect you are paying roughly similar amounts for DHW year round, so I'd put the difference down as heating costs...

Gooserider

 

[pjcassidy]

We do have a window A/C unit. It does run off 220V.

Thanks,
Patrick

 

[huffdawg]

Thanks leaddog. You kinda sound like my wife. "It's not that I don't think you can do it, you don't have time to do it."
You've been there and done it and it just doesn't always work like it is supposed to.
I'd looked into the HAHSA heater too....and read about people melting them down and such.

Patrick

Well I love to build things and I'm a scrounger and like to make do with things I find. I've made alot of mistakes and redone alot of thinks but enjoyed my journey. I'm very happy with the eko and the storage I have as I have done it cheaper than anyother way. Other people go other ways with other boilers. Alot of the decision comes down to how much you want and are able to do, space, time, resourses, codes, etc.
I bought alot of my stuff on ebay and at auctions. I bought 2 semi loads of propane tanks, Still have some to sell, bought LOTS of valves and pipe fittings, bought controls,and other stuff in quanities. I have a couple of BIG yardsales a year and resell alot of the stuff I don't use so it works out good for me.
But I don't think I will build another boiler.
Also after burying and redoing my underground piping 5 different times in all my expermenting I have finally got it right. Some times it doesn't pay to not do things right the first time.
leaddog

Hi,Leaddog! Im curios how you did your buried pex the 5th. time ,as I will be burying mine in a week and a half.
I was planning on spray foaming them but was not sure how much to spray on . It will be 1-1/4 80' long.

Cheers Huff

 

[sbleiweiss]

Patrick,
I recommend using the full kwh usage for the highest month for 2 reasons. First, most of the electricity consumed in the house is eventually released as usable heat. You can point to exceptions like a well pump, but for the most part things like refrigerators, televisions, ovens all release heat equal to their power consumption. Second reason is that this is a monthly average of heating and what you really need is to design for the coldest day or whatever you pick for the firing interval.

Your highest month was 4319 kWh last February.
4319 kwH * 3412.3 BTU/kwh = 14.7 Million BTU / month.
14.7 Million BTU / 30 days = 491,000 BTU / day.
If you have a system with storage that you heat to 180 and run down to 120, that is a 60 degree swing.
491,000 BTU / (60 Degrees * 8.35 lbs per gallon) = 981 gallons of storage.

Note a couple of things with atmospheric vented storage such as a Garn. You will need a heat exchanger to run a pressurized system in your house. The heat exchangers require some temperature drop to be able to move heat, so your delivered temperature to the house will be 10-20 degrees lower than the temps in storage. At least one well respected member here runs the house loop at atmospheric pressure thus eliminating the Hx temperature drop. Second, the boiling point of water is a function of pressure. If you run the water too hot, or have poor piping design, the water can boil at the inlet to circulator pumps where the pressure drops below atmospheric pressure. For this reason you cannot run storage temps arbitrarily higher with this type of system like you can in a pressurized boiler.

The above calculation does not account for your future expansion but does account for your DHW heating. You will at least want to pre-heat your cold water with heat from the boiler before plumbing it into your electric hot water heater. The calculation also assumes 1 burn per day in the cold periods.

Good luck,
Scott B.

 

[pjcassidy]

I'm going to use radiant floor heating, will I still need a heat exchanger? I thought I could just run that straight to the house.

 

[Gooserider]

I'm going to use radiant floor heating, will I still need a heat exchanger? I thought I could just run that straight to the house.

The usual recommendation is to run a pressurized system everywhere except the Garn itself, and possibly the lines to - from the house (you will find folks that argue that both ways) If you are going to tie into an existing fossil system, which is almost certainly pressurized, then you DEFINITELY should use an HX to keep the existing system under pressure... There are a lot of different reasons for this, but they all boil down to the fact that a pressurized system offers a great many advantages which generally make it worth while. (Pumps work better, fewer corrosion issues, easier to deal with multi-floor dwellings, and / or height differences between the Garn and the loads, etc..) There are some people that run all non-pressurized systems, not to mention the folks that have what I call the "European Open" systems which act like a pressurized system due to the laws of physics, even though they are technically open.

One thing I would STRONGLY advise, even if you do decide to run some or all of the system as open, is to spend the few dollars extra to make ALL the PEX in the system "O2 barrier" type - it is good "future proofing" - we have a few members who put in non-02 barrier when installing their OWB's, and then switched to a gasser and found problems because they couldn't go pressurized...

Gooserider

 

[pjcassidy]

So....ok.
I'm planning on using radiant floor heating with PEX-a tubing.
This is a "new" installation, although the house is 8 years old. Like I've said, I currently use electric baseboard heating. There is no ductwork in place.
Should I put insulation on the inside of the concrete block crawlspace? Do I need to use metal difuser plates? Do I put insulation between the sills, under the tubing? What kind of insulation to use? I've seen two or three different ways that are supposed to be the best way to do it....

Can someone give me a laundry list of what stuff I'll need?

Thanks for all the answers guys.
Patrick

 

[Gooserider]

So....ok.
I'm planning on using radiant floor heating with PEX-a tubing.
This is a "new" installation, although the house is 8 years old. Like I've said, I currently use electric baseboard heating. There is no ductwork in place.
Should I put insulation on the inside of the concrete block crawlspace? Do I need to use metal difuser plates? Do I put insulation between the sills, under the tubing? What kind of insulation to use? I've seen two or three different ways that are supposed to be the best way to do it....

Can someone give me a laundry list of what stuff I'll need?

Thanks for all the answers guys.
Patrick

This is not an easy thing to do, as the details are tremendously dependent on exactly what your house construction is like, climate, how you want to do the install, and so on, just for starters, before you even start getting into people's personal prejudices about preferred approaches, equipment, and such...

In general, one of our constant themes is that insulation is good, and more insulation is usually better - and that air-sealing is critical. Getting the air-sealing and insulation down right will give much better paybacks than anything you can do with a heating system... So yes you will almost certainly want to insulate the crawl-spaces and floor, and around the sills - Spray foam seems to be the preferred approach for the sills, and lots of folks like it for most everything, but it tends to be expensive, and arguably less DIY-friendly than some of the other approaches. I generally like to send people to Building Science for the details of how best to do insulation depending on their construction.

If you are going staple-up, diffuser plates should definitely be used, along with appropriate insulation under the tubing and plates. Note though, that even the best staple-up has very serious limitations about how much heat it can deliver, depending on the thickness and nature of the floor and what sort of floor coverings are in use. It may be worth considering pulling up the existing floor and doing some kind of above the subfloor install, especially in those areas where you have a high heat load (those cathedral ceilings you mentioned) This is where your room-by-room heat load calculations come in handy as you need to see if infloor is even going to be able to deliver the BTU's needed - you may need to add some radiant wall, or flat panels as supplemental heating...

If I was doing a staple-up job, I'd probably go with plates, and then a "bubble-wrap" radiant barrier an inch or so under the tubes, then either sprayfoam under that or possibly fiberglass to the bottoms of the joist cavities, and then cover the entire underside of the floor with foam-board, taping and sealing all seams... However I'd be more inclined to go with trying to get the tubing above the subfloor... (As a side note, this is the thought process I've been working on somewhat for our own home if I can ever get the $$s together to do a gasser install...)

Gooserider

 

[pjcassidy]

We have linoleum in the utility, tile in the BR and hall, laminate in the kitchen and bedroom, carpet in the living room (but it will be going away). My wife would really like to replace everything with wood flooring. 3/4" T&G subflooring. I hate to think about pulling up all the flooring, as we had a flood in the house a couple of years ago and everything is "new".
"If I'd known...." I'd have done things different.

Thanks for all your information Gooserider,
Patrick

 

[Hunderliggur]

A very good primer on radiant heating can be found at http://www.radiantdesigninstitute.com I also found the The Radiant Floor Company http://www.radiantcompany.com/ to be a great help and a good supplier. My radiant floor heat is tied in with my domestic hot water. All the domestic hot water runs through the floor first before being heating for the house. This keeps the system from being stagnant during the non heating system as you use domestic hot water. The radiant tubing is 7/8" PEX which was OK for new construction with open web trusses (7/8 tube does not bend very tight). For a retrofit crawlspace I would definity consider 1/2 PEX. The Radiant Floor Company was able to do heat loss calcs based on my parameters and size the zones and circulators accordingly.

 

[pjcassidy]

I've looked at both those sites, they have somewhat differing suggestions on some things.
Do you have a cathedral ceiling in your cabin there? We have cathedral over about half the house, with an open loft, huge cuft. of air, and it is always 5* warmer upstairs than down.
How does Radian Floor Co. charge for that service?
Thanks,
Patrick

 

[Hunderliggur]

Believe it or not, we do not have cathedral ceilings in our "cabin" (about 4000 sf). This is our 3rd house we have built for ourselves and don't see the value in cathedral. We do have 9 foot ceilings in the entire house (basement included). The Radiant Company provides the calcs free as a way to get a proposal for their equipment in your hands. I was very happy with them. I believe you fill out a web form with your info and they take it from there. [BFORE I GET FLAMED - This is a SIMPLE calculation but when you are dealing with radiant AND storage you can have some approximations. BTW - It came out VERY close to the professional heat loss calc I had to pay for locally for my mechanical permit). What do you find differing between the sites? I used Seton's first then ordered through Radiant. They have a great installation manual. They say you can do "hundreds of feet a day of PEX install". My team agreed - you pull each 300 feet through the trusses several times when you are installing the loops! I have two zones with 7 loops x 300ft and one zone with 5x300. All are 7/8 PEX with aluminum plates. Radiant is a good way to go with cathedral since you are heating the objects not the air. Your floor and furniture will be warm.

Our floors are mainly 3/4 bamboo and Marmoleum in the bathrooms and laundry. There is tile in the master bath and jacuzzi room.

 

[Gooserider]

One of the big issues that I have with Seton's site, which does have a lot of good info on it as well, is that he advocates plateless installs - IMHO this is a really bad idea - do a search for a link to Siegenthaler's article "Plateless in Radiantville" for an alternative opinion from one of the top guys in the industry...

Gooserider

 

[Hunderliggur]

I would not do plateless with PEX (Ok with copper tube I suppose). The physics just don't work for me (and I am a physics major). Anything to increase the thermal transfer fom the PEX is a good idea - plates or concrete.

 

[pjcassidy]

That "plateless" is part of what I meant. One site says not to have runs of more than 300', another says 500'. I think one suggests only using 7/8" PEX, the other says 1/2" is ok.

 

[Hunderliggur]

It is all a matter of design concepts. PEX only radiates so many BTU's t the surrounding space based ofthe temperature differential. The plates dissipate more BTUs to a larger area, thereby increaing the number of BTUs delivered per foot.

Pipe size and length affects the head (pressure) that the circulator will encounter. Larger pipe, less head, smaller circulator. 7/8" gives very little resistance and you can user a lower power circulator. There are calculators that will let you compute the head for any size pipe and length. Shorter runs from the manifold means you will have less total temperature drop on the line and a more even heat distribution.

Personally, I like the low pump power requirements from using larger PEX, but larger PEX is harder to install. It is all tradoffs. In the end I installed the design provided by the Radiant Floor Company and it works for my installation.

 

[heaterman]

We use 3/8" or 1/2" tube for underfloor apps and plates depend on the heat requirements of the structure or room it's going into. I would never ask my guys to install 3/4 or 7/8" pex under a floor. The simple reason is that they would probably leave me the next day.
Another thing I consider is the floor covering. Plateless installs are prone to striping and this will be more pronounced under a wood or laminate floor than tile. Denser products will spread the heat more evenly. Probably the single most important thing to consider is the heating load.

We did a new house this summer with 1/2" a pair of 1/2" tubes suspended in each joist bay using R-11 insulation underneath it. Works great but I have to say the heat loss per sq ft in the house was only 13 or 14 IIRC. The cut off point I use is around 16-17 btu/ sq ft for running without plates. Anything past that and a person has to use high water temps to get done and you WILL get noticeable temp variation in the floor.

An infrared scan of a floor with no plates and tubing stapled tight to the subfloor is an eye opening experience. Nothing I would want in my house. It's a completely different animal.

 

[Tony H]

Have you considered radiant panels for some rooms ? Could save some time and use for bathroom ,laundry room or ?

 

[pjcassidy]

I hadn't thought about radiant panels, because, actually, I didn't know they existed till recently. The utility would be easy, since that is where the manifold will likely be, and the BR is right next door. But I'd really like the bathroom to have a nice warm floor!