Hydronic (hot water) heating systems - based on boilers and radiators/baseboards, or on hot water radiant floor heating - are often described as the healthiest and most comfortable type of home space heating.
Unfortunately, most hydronic systems are expensive to buy, install and to run for single family homes with low or moderate heating requirements. They are designed to meet large heating requirements.
In other words: like furnaces and other central heating forced-combustion systems, boiler systems (hydronic heating) may not make sense in very energy-efficient homes, even in cold climates.
Typical hydronic systems are complicated and expensive for very energy-efficient single-family homes. Radiant floor heating is a good example of it. See: Radiant Floor Heating Guide.
Prices and Heating needs
Homes with a good design and windows, and with high levels of insulation all over their shell, have small heating requirements.
A small ductless mini-split heat pump system, or other small ductless heating system can provide high levels of comfort and meet all the heating needs of these homes, even in cold climates, at a much lower cost.
In other words: unless you consider a small system (based on a European-style boiler...), hot-water space heating rarely makes sense in low-energy homes.