My house currently is heated by a hot-water boiler, with radiators in the main rooms. The bedrooms have no radiators (it's an old house and I guess when it was built they figured the central radiators were enough, which they are if you leave the bedroom doors open a bit).
The boiler is nearing the end of its life and I'm wondering if there is any reason why I couldn't replace it with wall-mounted ventless gas heaters (like this, as an example only: https://www.homedepot.com/p/Dyna-Glo-30-000-BTU-Natural-Gas-Infrared-Natural-Gas-Wall-Heater-IR30NMDG-1/206556628). I'd make sure the total BTUs met the requirements of the space. (I'd also make sure my carbon monoxide detectors work, just in case, given that these are ventless.)
Would this create any code violations or other problems? It's common in my area for folks to install one or two of these in their houses as auxiliary heat, but I've never heard of anyone using them as their only heat source, so I'm curious.
Best Answer
If it were me I would investigate the ability to use the existing boiler to heat the entire house. You said that the boiler is reaching the end of it's useful life; please explain why you think so. Hot water boilers can last as many as 100 years. At that age they are not usually very efficient but they will still heat a home or building. With a useable boiler you have many options to extend the heating system into the unheated rooms. Using unvented heaters as you mentioned is not a good option. You will have the smell, the excess humidity, running new gas lines to each one, the depletion of breathable oxygen and other things to consider. I would never use one of those heaters in a confined space or room. They are cheap for a reason. Go find a good boiler guy and investigate your options using the old boiler. my 2 cents