Coverting to gas - New boiler size question.

Speedyjoey

I am converting from oil to gas heat. I live on long island (New York) and im looking into the Burnham ES2 boiler. My home is a HiRanch. Two zones, one on each floor. The house is about 2,450 SF. Built in 1985. I would like to know which unit to go with. Not sure how many BTUs I need.



Thank you

Joe

Steamhead

Find out

how many BTUs you need. We do this with a heat-loss calculation program which takes windows, insulation etc into account.



There are plenty of contractors on Long Island who could do this for you. Try the Find a Contractor page of this site.

Speedyjoey

Thank you.

I had three people come in. One recommended a 130 BTU unit and two others recommend the Burnham ES2-5 140 BTU and the last guy say that the Burnham ES2-4 105 BTU would be good. I'm am just really confessed which unit will be best.

Tim McElwain

Ask each contractor

how they determined the boiler sizing. Did they all actually do a heat loss and also  measure your lineal feet of baseboard.



Find out who distributes the Burnham boiler in your area and give them the info on your house and see what they recommend.



Ask the contractors for references as to other customers that they installed this same Burnham boiler for and see if they are satisfied

Speedyjoey

No

Two measured the base board other 2 just looked at the old unit. If there a way I can calculate what I would need by using the homes square feet?

CMadatMe

Budget sizing

Rules of thumb for budget sizing based on a 0 degree climate and a 70 degree set point.



R-19 Walls, R-30 Attic, Good Windows = 25 btu's a square

R-11 Walls, R-21 Attic Decent Windows = 32 btu's a square

Have no clue then 40 a square.



A betting man would put his money on that boiler quoted is oversized. Why an ES2 and not a condensing boiler? By the time you line that chimney which is required for an ES2 your in a condensing boiler price point.

Steamhead

Not always

if there's no safe place to vent a mod-con thru the side wall of the house, you have two choices: Either use a chimney-vented boiler, or use the chimney as a chase (if that's possible) for the mod-con's air and exhaust pipes.



The latter would preclude the use of a standard gas water heater in the same chimney, making it necessary to go with an indirect or some other type of water-heating device. This would make the job cost a lot more, possibly more than relining the chimney, so a chimney-vented unit like the ES-2 series looks a lot more attractive. And many times it's more efficient than whatever is coming out!

Speedyjoey

thank you for your help. Just thought it was weird how they all had recommened different units

one recommended- 130K (Kenmore), two recommended the 140K (Burnham ES2-5) and the last guy said (96K Burnham P205) or the ES2-4 (105K)

Speedyjoey

Would it be bad to get a unit that was a little larger?

I was thinking about getting the larger unit since it was only $150 more. Wouldnt the larger unit heat up the house faster?

Robert O'Brien

NO!

Unlike most things in life,bigger isn't better when it comes to boilers! Just did a heat loss on a 2900 sq/ft house in Shoreham,LI. Came out to 57K. A larger boiler short cycles and will use more fuel

Steamhead

Bob's right

a heat-loss is the only way to go- unless it's a steam system, then we size to the radiation.



But in either case, oversizing is doubly wasteful. It costs more to buy and more to operate. The only ones who benefit from this are the oil and gas companies- is it any wonder they oversize so much?

Speedyjoey

Is the the input or output BTU?

I'm still not sure with would be best: My home was build in 1984 so I assume I have some isolation. And I have two zones. and heated sf is 2410 

Burnham ES2-4  105/77 (Btu in/out) or

Burnham ES2-5 140/102

Steamhead

You need much more info than that

a heat-loss calculation considers much more than the square footage of the house. 

gennady

boiler sizing verification

Another way of sizing the boiler is trough heating degree day.

It actually gives you input for old boiler you actually used, and then  you do efficiency improvement correction factor and arrive to proper size. When i get boiler size 4 times smaller then existing boiler, i do this and usually a m spot on with less then 5% difference.. do not forget pickup factor, as HDD is reflecting more steady state operation.