"If I get the chimney lined appropriately, is that an ok route for sending the exhaust? "

It is the condensation from the high efficiency boiler, and unless you can keep it form freezing it is going to block the chimney.

The flue must be kept short and warm enough to get the moisture out of the flue.

Thanks for this. The lower 1/3 of the chimney is indoors (meaning the first floor and the basement). It is exposed to the outdoors on the second floor and up to the top of the chimney. Would the freezing/blocking occur up there toward the top or is the concern normally further down (where perhaps in my situation it won't be a problem).

Thanks again.

Generally venting a high efficiency boiler through a chimney is NOT a good idea.

There have been cases where the condensate has literally filled the flue with liquid.

ok, I hear you. Thanks. Still waiting to hear from contractor.

Somehow I need to get this steam away from the window ... not sure what I'll do. Options to route to other exterior walls don't look good either. If there is a smart fix, I'll post on here.

thanks again.

Well, could you extend the pipe farther away from the house? Not a great solution, but it might work.

I would really like to see a model number and brand name for that boiler.

There are codes restrictions about proper clearences to windows

And this sounds like it might not meet the manufactures specs

Ask the contractor what could possibly happen to you if that window were opened in the winter and the boiler was burning dirty?

If you post the brand and the model number we could check the installation instructions and see if this is even allowed

How far away in inches is the window from the outlet of the exhaust?

It seems like you need a condenser of some sort outside with the outlet pointed down so the water drools out on the ground. You can see the problem with that, though. You will have a big slab of ice on the ground in no time.

Why is this not a problem with all direct-vent high efficiency furnaces and boilers? The dew point is high and the temp of the exhaust is low. Condensation happens immediately when the humid exhaust hits the cold, damp outside air. One approach that could fix this is to mix outside air with the exhaust very quickly. Run the exhaust into a a chamber with a second inlet and an outlet to handle the combined flow. Tie a blower to the furnace that blows in 10x the amount of outside air compared to the boiler exhaust. You get turbulent flow. With any kind of luck, you will have built a snow machine. The fact remains that lots of people have high efficiency heaters in cold climates and they don't have this kind of Rube Goldberg arrangement or ice palaces outside of their homes do they?

Contractor and I are still playing phone tag.

Johnhvac - It is a Burnham - Alpine 95% efficiency gas boiler. ALP150N-LO2 is the model number.

Distance from mid exhaust to bottom of storm window is about 31 inches.

kframe19 - extending it out further is an option but it is already visually ugly (we live on a corner lot and the back of our house is fairly visible to all - plus our driveway is in the back and we are in the back yard a lot). Plus, we still have the site of all the steam.

I was really hoping to have this sent up the chimney but I get the concern. If we have a liner and also have a water catch w/pump at the bottom, still no go?

Hey, Gar9000, did you end up finding a solution? My high-efficiency boiler vents out the *front* of the house, and and the clouds are ugly and unappealing as the new main view from the living room window. It's also killing of the landscaping, although when I asked if that would be a problem they assured me that it would be cool enough by the time it exited that there would be no damage. I was also hoping there was a way to vent up the chimney.