I am tbe OPs brother and trying to help him understand his options. heres my question ... cant his new gas boiler be vented out the side of the house rather than through the chimney? Forced hot air systems are vented that way. Any reason why his new boiler can't be vented that way?

You would need a boiler with an efficiency of 90% or higher in order to vent out the side of the house. There are some choices available but not as many as furnaces.

Installing a liner in an old chimney is probably a good move. The installation is going to vary on the difficultly of the installation.

They are quoting him $3k to install a chimney liner. i would think that uogradinf to a 90% efficient bouler would be less than that. Right?

Anybody know about state or utility incentives in Massachusetts to upgrade to a more efficient boiler?

There are plenty of high efficiency boiler choices out there. If it is possible to locate a plastic vent out the side of the home, you are probably better off going that way than to install a chimney liner. Understand that there are different kinds of chimney liners. Depending on your particulars, you might be considering a low temperature plastic flue or a clay liner. Are you replacing a gas-fired boiler with like?

You should know that it can be tricky to replace an old, high mass boiler with a high efficiency low mass boiler. First, the match to the emitters (radiators, convectors or hydrofoils) and the heat loss from the home must be very good. Homes that have heat cut into small zones can complicate things because the boiler may not be able to modulate to supply smaller zones while having a hight enough capacity to heat the whole house in colder weather.

Here is a link I found to masssave.com rebates. It looks like a 90%+ boiler would qualify for a $1000 rebate. Purchasing a high efficiency boiler makes sense in Massachusetts. The challenge is purchasing the correctly sized boiler for the current heating system.

I think $3000 to install a liner seems excessive. Does the hot water heater use the same chimney?

Unfortunately, it is even more than sizing right that will influence the probability of success with a HE boiler. I hope that the OP has some time to figure this out rather than now sitting in a cold house with a failed boiler

If the home has excess emitter capacity, there is a higher probability that a HE boiler will work well due to that ability to run at lower temperatures. If small zones exist and are desired, mass might need to be added to the system in the form of a buffer tank or something like an HTP Versa boiler. People have also combined zones to make systems more effective I don't think that there are many installers that can effectively cope.

I'm the OPs brother. He is indeed sitting in a cold house - a week now - with a cranky wife and two kids. I think he is getting something installed tomorrow. Thanks for the input.

Is there a liner there already? Dangerous to vent out of old chimneys without a liner. Otherwise upgrade to the high efficiency boiler and they can run PVC (intake and exhaust) up the chimney and use a new cap for the PVC.

FYI the high quote is because furnace grade ductwork is expensive. It is not standard flex ductwork, it is much higher gauge. Has to withstand the higher temps.

My sympathies on the cold home. If I had to do this in a hurry, I install an HTP Versa providing DHW and heat. They have a very nice boiler design that is hard to screw up with installation details. If only heat is needed and it is big enough at 76,000 btus, a Westinghouse hot water heater (WGR050076) is essentially the same thing for a bargain price the last time I checked. It is a 97% efficiency, modulating (25,000 btu minimum) appliance. You could add a flat plate heat exchanger to provide DHW These solutions provide a plug-in replacement for an old high-mass boiler so you don't have to redesign the rest of your system. If you want to get heat in a hurry, you could just install a hot water heater temporarily.