When it comes to installing hot water baseboard heat there are several different scenarios that make the resulting installation job either quite simple or a fairly large undertaking.
Scenario one. You have a forced air heating system (it uses your air conditioning ducts) and want to upgrade to a better heating system... In this situation you will need to do some work to get baseboard heat hot water systems in place. The first question should be Do I Need It?
In some situations the hot air scenario is sensible - depends on how much heating you need. In Southern Florida, for example, it might not be worth the cost and trouble of installing central heating since it will not be well used. Improving your insulation might be a better start.
Hot water baseboard heat needs a boiler, a pump, a series of pipes and the baseboard units. This is not a huge job compared with some household projects and an installation can be done in a day or two, depending on your home. Therefore it is worth looking at if you really feel the lack of good heating in winter, even if you currently have a ducted air heating system.
Baseboard radiant heating systems can, at the other extreme, be very simple to install. In scenario two you already have a central heating system in place. In this can it is simply a case of switching over the radiators for the smarter, more modern, baseboard units. Do not miss the chance to have local thermostatic controls put on your units - it will help you save energy by zoning your home according to the heat needed in each room.