Gas Boiler

sioux

I need a new gas boiler, direct vented with existing hot water tank attached, and am looking at a Lochinvar KHB-155 or Weil-McLain GV90+5. Has anyone had experience with these and any recommendations?

Thanks
Sioux

Snowmelt

w/m Gv 90 is good , I like it , just heavy to get down a set of steps,. where are you from?

sioux

Greater Boston

HVACNUT

Was a heat loss calculation done?
How did you figure the BTU rating you need?

Jamie Hall

Are you sure those are the right size? Anyone done a heat loss calculation?

3zht

I have the lochinvar knight 085 with an indirect water tank. It heats my 2700 sq ft with 135F water temp. It's a pretty amazing machine and has literally cut my gas bill in half.

sallaberry

If I had a choice lochnivar hands down.

sioux

The issue is my family room has A LOT of glass, 12 windows.

Jamie Hall

A lot of glass, @sioux , is going to be a problem -- in fact, two problems -- no matter what boiler you pick. The first problem is solar gain. Depending entirely on orientation, of course! But if the orientation is towards the sun -- anywhere from southeast to southwest -- there will be days on which the solar gain is in excess of the heat loss, sometimes greatly in excess (a handy number is somewhere around 3000 BTUh per square meter of glass). You need to find a way to either move that heat somewhere useful -- or open a window and dump it (note that interior drapes or blinds don't help much -- once the light gets through the glass, the heat is there). The other problem, obviously, is heat loss when there is no sun. You need to be able to get enough heat into the space.

Unhappily, it is likely that the rest of the building -- unless you have a good way to move heat around -- is not going to have the same loads at the same time. For which reason a space like that really should have its own zone -- nothing else on it -- and its own thermostat.

Larry Weingarten

Hi, Following on @Jamie Hall observations, you might want to look into low-E storm windows to go over your dozen ones, particularly if South facing. They would reduce both heating and cooling loads.... and make the room more comfortable!

Yours, Larry

Ironman

Unless you have a house that's 5000 square feet +, both of those boilers will be way over-sized - a cardinal sin in hydronics.

Putting in a boiler that's too large won't fix heating the family room, in fact, it may exacerbate the problem because it will sort cycle.

I agree with Jamie: do a load calc. That's the first step. SlantFin has a free app that you can download for this. Second, put the family room on its own separate zone.

lchmb

personally if it were my house I'd go with the GV90. I've installed a number of them and love the ease of maintenance.

Zman

A heat loss calc is the only way to get this right.
You can determine the max amount of energy your system can absorb by counting your radiators. Do you have baseboards?