High Efficiency Residential Boilers Mfg??

NY_Yankees_Fan · Feb 15, 2004

Does anyone know of any high efficiency boilers? I found this company link and it looks like this is state of the art boiler, claims 30-50% reduction in fuel cost. My 17 year old natural gas boiler is at best 50% efficient and I think maybe too small for our house, it seems to run all the time, and out gas bills seem to be going up, last one was $550. We have a tankless hot water 80 gallon and 3 zone hydronic system. With the tankless heater, installed in 1999, the boiler runs year round. House is 3,000 sq. ft., 17 yrs old, R11 in the walls and R 30 in the attic. Boiler is rated at 95,000 BTU input. I expect to be in the house for another 10-15 years. Nothing wrong with the existing boiler. Am I nuts to replace, or do you think the savings in fuel would payback in a few years? Any idea on how to size the BTU of the unit I would need? and how I would calculate potential fuel savings?

bebster · Feb 15, 2004

Tom,
As a Red Sox fan, I'm happy to give advice (even if you guys did steal A-Rod)! You might get one of the software packages that does all the calculations on heat loss, etc. Although there might be rules of thumb, I think all the variables you mentioned are well modeled by these packages.

I believe a friend of mine just put in one of these high-efficiency European LP boilers, might even be the MZ you indicated. He's really pleased with its performance. I'm building a new house and am considering it as well.

It has dual outputs - one at higher temps for hot water, and another at lower temps for hydronic heating coils.

PineRidge · Feb 15, 2004

Tom I have always preferred Carrier/Bryant equipment. Have a local heating firm do a heat loss on the home so that you don't end up with a boiler that is too small or too large. Higher efficiencies will save you a bundle over the life of the equipment. Especially if you are talking high efficiency and comparing it to your old 50% eff. boiler. Most reliable heating dealers will also have a software program that will chart the savings for you based on the efficiency that you decide to go with on the new boiler. Keep warm. /forums/images/graemlins/grin.gif

NIXON · Feb 16, 2004

Tom , Take a look at www.takagi-usa.com .
I have a tk-1 in my house and it's been flawless ( 3+ yrs . )
I only use it for domestic water heating , not for heating the house . But it has no trouble supplying water for two showers at a time . A sort of wierd , but useful feature is that it has a remotely mount temp control box( optional ) . You can vary the water temp from 100- 168 Degrees . The remote does have one downside , if you lose power it shuts off the boiler ,and you have to manual turn the remote back on ( at the remote ) . As your in the market , it might be worth looking at . John

BXMMCC · Feb 16, 2004

Google Bosch Aquastar!

_RaT_ · Feb 17, 2004

Are you looking for a boiler for the hydronic heating only or the domestic water heating or both? What is the tankless 80 gallon in reference too? I used a tankless heater for domestic water heating for a number of years and was not impressed. I am currently looking into a high efficiency boiler for our radiant floor heating system we are considering installing in our too be built new home. If yours is at 60% or less effciency, I would suggest you start looking. A gurantee is that natural gas prices will not be going down especially at the rate the new natural gas fired electrical generating plants are being built. The demand for natural gas is huge and getting bigger all the time. The "highway" to carry it is adding to the problem.

NY_Yankees_Fan · Feb 17, 2004

Rat

I am looking for a boiler to supply hydronic hot water and supply the hot water tank.

The 80 gallon tank is located next to the boiler and is supplied hot water from the boiler via a zone valve to a coil in the tank.
We had to go to a 80 gallon tank because of the 2 person jet soaking tub in our bathroom that we use about 2-3 times a year. /forums/images/graemlins/tongue.gif

So far I have found the following:

link

This web site actually sells everything you need including the boiler. link $4K just for the boiler. Figure another $1K to install, $5K total, my annual heating bill is about $2K, at 30% savings, $600 a year, 8 year payback, got me thinking and the CFO. So we are going to add more insulation in the attic and bring it up to R44 from R30, reprogrammed the thermostats to keep the house at 67F at night when sleeping, down from 69F, and see what that does. Going to borrow an IR camera from work and see where my heating loss is and try to fix that. If natural gas prices keep going up, I will end up switching anyway, but at least the CFO will know we tried everything. /forums/images/graemlins/grin.gif

_RaT_ · Feb 17, 2004

Heres a link I found to a well known boiler/water heating system.

Heating Solutions

dmccarty · Feb 17, 2004

NY Yankees Fan,

I think you are on the right track with insulating the house. I
was reading through Richard Truthoy(sp)'s, the HVAC guy on
This Old House trying to find info on what you and I are doing.
He said for an existing house have an energy audit performed.
But since that requires the use of a blower door I'm not sure I
would be doing this in the winter.

He did say the cheapest think to do would be caulk up the
house and had insulation. Then look at the HVAC systems.

Modern equipment is more efficient the longer it runs. The
cost is at start up. I'm pretty sure my Heat Pump is to big for
my house so it starts frequently which is the expensive thing
to do. The energy/dollar cost is a sharp curve up at startup
time and then drops drastically there after.

Rats comment about gas being more expensive is almost
certainly correct. There was a story today in the Wall Street
Journal talking about the demand for gas and the corresponding
spkie in prices. The increased demand is due to the
government pushing gas since it burns clean. There also is
very little domestic searching going on for more supplies,
supposedly due to environmental regs, and the domestic fields
are getting old. Because of this chemical and plastic
production(jobs) is going to flow overseas. /forums/images/graemlins/frown.gif

Try http://www.radiantec.com. They have lots of
info on radient heating systems. I don't think this is what you
are really looking for but they have some rule of thumb
formulas to calculate how many BTUs you need to heat the
house. The also have some boilers that might be interesting.

For BTUs, my new house which has R20-25 walls, R35-40
ceilings, and 2500 sq. ft. requires about 40,000 BTU to heat
But I'm just a wee bit farther south than you! /forums/images/graemlins/grin.gif

Just had a thought? Does the maker of your current boiler
have a website? Maybe they have info on your particular
model requarding sizing?

Later,
Dan McCarty

r0GuE · Feb 17, 2004

I have a Buderos system with integrated indirect hot water heater. I am very very happy and they told me it is state of the art. It is manufactured in Germany which used to make me happier than it does now (pre-gulf war II).

http://www.buderus.net/

I love mine!

NY_Yankees_Fan · Feb 17, 2004

Dan,

Great idea!I sent an e-mail to the manufacture to find out what the energy rating is. Burnham web site also had a calculator to calculate total heat loss to determine the size of a boiler as well as the savings of say 75% energy effency vs 95% energy effency.

Used the IR camera today and found that my outside walls do have insulation in them. I was really concerned that they did not insulate the walls when the house was constrcuted 17 years ago.

This weekend we will add the extra insulation in the attic. I have R19 and then a layer of R11. I am going to remove the layer of R-11 and replace it with R25 which will give me a R44, which will help I am sure. I would go with R-30 but can only find it in kraft face and do not want to deal with removing the kraft face paper.

dmccarty · Feb 18, 2004

Tom,

Why are you going to remove the insulation in place? Can't you
just unroll the new insulation over old and get that much more
R value?

Our current house is almost 30 years old. It was energy
efficient for its day and I know it has insulation in the walls(R11)
but it sure is cold! I really wish I knew then what I know now
and I would have torn out the old prefab fireplace and put in a
new efficient one. We sure would be warm in the winter....

Later,
Dan

NY_Yankees_Fan · Feb 18, 2004

Dan,

Wife asked the same question. Problem is the attic has no floor so I will have to walk on the joists. Kinda hard to see where you are walking with 4 inches of insulation laying on top of the joists. I do not want to walk and go between the joist and through the sheet rock ceiling.

Tom

Libertine · Feb 19, 2004

NY_Yankees_Fan:

If you are looking to replace a boiler, you should consider going to oil fired for a number of reasons:
1) Much safer.
2) More available/flexible (can use diesel fuel, cooking oil, etc.) in emergency.
3) Cheaper (higher btu per dollar).
I have hot water in floor radiant with almost no ceiling or wall insulation, a lot of floor to ceiling glass (no attic) and have averaged only 800-900 gallons per year for 15 years. House smaller than yours and a bit further south, but poor insulation, etc. probably makes up for size difference.

JEH

dmccarty · Feb 19, 2004

Tom,

Ahhh, I see afraid of the Air Step. ALMOST done that. /forums/images/graemlins/grin.gif

Can you take some planks or cut down plywood to lay across
the joists so you can walk safely?

I've been thinking about this since I really want our new house
to have a R38+ attic PLUS storage....

Later,
Dan

bcarter · Feb 19, 2004

I really want our new house to have a R38+ attic PLUS storage.... 

I had about 6-8" of loose rock wool insulation in my attic that had no vapor barrier behind it. I pulled all of that out (by hand!) and layed in a 8" layer of fiberglass with attached vapor barrier. I then built an elevated platform using rough-cut 1x12 (full 1" thick and full 12" wide) that rested on the ceiling joists (going the opposite direction with the spacing of the platform framing set such that a 24" batt would fit neatly within). I then layed out 12" thick unfaced insulation perpendicular to the 8" on top of the ceiling joists and inside my platform. With a floor on top I had attic storage AND 20" of fiberglass insulation.

This made a HUGE impact on the amount of heating oil I used as well as making the house much cooler in the summer.

dmccarty · Feb 19, 2004

bcarter,

I have rock wool in my current house. When I bought the
house I planned on adding more and never did. I have been
paying for it every since.....

On your attic, how did you attach the 1x12s to the joists? Just
toe nailed them or did you use brackets of some kind? If I
went WITH the joints I could put in strips of plywood or plates
to keep the "platform" from racking. But if I went across the
joints I suppose the tie straps would work and the "new"
insulation would cover up the joists which is a good thing....

Later,
Dan McCarty

bcarter · Feb 19, 2004

> I have rock wool in my current house. When I bought the
> house I planned on adding more and never did. I have been
> paying for it every since..... 

My original concern was the lack of vapor barrier, but I noticed a big difference even with just the new 8" of fiberglass. I did the additional 12" the following year difference there was large again.

I have to tell you that getting that rock wool out was a job that I would not want to do again... I was literally taking it out one handfull at a time and stuffing it into trash bags. 1000 sq ft of attic took the better part of a month working nights and weekends but in the end I was glad I did it.

 > On your attic, how did you attach the 1x12s to the joists? Just
> toe nailed them or did you use brackets of some kind? 

I just toe nailed them where the 1x12 crossed the joist. Actually I used deck screws, so I guess you could say I toe screwed them... /forums/images/graemlins/smile.gif

 > But if I went across the joints I suppose the tie straps would work and the "new"
> insulation would cover up the joists which is a good thing 

My intention was to have the 12" layer of insulation cover the joists and any gaps in the 8" layer. The 1x12s I used were 8' long (longest I could get into my attic) so I basically built boxes that were 8'x8' with dividers in the middle. Between the toe nailing, the plywood top, and the 1x12s end nailed into the cross pieces, they were pretty rigid so I didn't worry about racking. I suppose a few pieces of bridging in the middle wouldn't hurt if you were worried about this (or were using longer 1x12s).