We have a 3-unit multifamily home with radiator heat (about 2400 finished square feet on 3 levels) in the DC area. I was shocked at my $350 heating bill for November, but was absolutely blown away at my $500 bill for December. Can I replace my boiler (it's at least 20 years old) with a tankless water heater to save money and energy?
presumably you mean a combi boiler which gives instant hot water while also providing circulated water for the radiators, it is possible to fit those but they don't last, they are expensive to fit and they don't save much money, it is gouging by the power companies not your boiler that is to blame
There are domestic water heaters that are also rated for heating purposes - Takagi (linked below) is one maker in this business. They run at about 84% efficiency, modulate to a degree and would work for low-demand applications. In your specific case, you would likely have to install three such systems on separate zones as one will not do the job and they do not like being ganged up as is possible with standard systems. They are also not cheap (except as relative to a heating boiler). You will be better served to install a high-efficiency modulating boiler of the proper capacity to heat your property. Using our house as an example, it is a bit over 4,200 square feet, was built in 1890, has 32 radiators on three floors with ceilings over 9 feet. Our December energy bill (gas and electricity) was $542 (southeastern PA, gas at $1.17/therm) and we keep a comfortable house. We installed a Weil-Mclain Ulta boiler (linked below) that also makes our domestic hot water. And, if you use a modulating boiler, there is no operating penalty for being over-sized - which you can do at a very small incremental cost for peace-of-mind.
you can have an unvented cylinder which works from mains water an example of this here www.inspiredheating .uk/cylinde... but really your problem is that your heating system is old, old boilers run at about 65% efficiency - i.e. the amount of energy used will be converted into 65% heating so some is lost in the process. new boilers - high efficiency condensing run at 98% so about 33% better than your old boiler. this boiler would have saved you $165 off that $500 december bill. Also all your radiators need thermostatic radiator valves, so in times of high demand you can control which rooms get most heat and which need little heat, this will save your boiler heating rooms that probably arnt even being used.
Tank less, NO! New, High efficient boilers that consume less space are available and with rebates. Pay for a assessment and perhaps a energy audit. Since you have tenants, use only licensed personal.
Tankless Water Heater And Boiler
