Use a portable space heater (or multiple space heaters) when a larger heating system is too costly to install and when the space is small enough to be adequately heated this way. Space heaters have btu-per-hour capacities of 10,000 to 40,000, and they most commonly use electricity, propane, natural gas or kerosene.
Choose a space heater that uses convection instead of radiant heating.
Purchase a model with current safety features, making sure that it has an Underwriter's Laboratory label on it.
Avoid wasting energy by choosing a space heater controlled by a thermostat.
Read the sizing table on the heater or product box to make sure the heater is capable of heating a space of your size.
Set the heater away from areas of heavy foot traffic (from people and animals).
Steam radiators or baseboard heat is an alternative if the building has its own water source.
Choose an energy-efficient piping layout. When hot water leaves the boiler, it transmits heat as it travels through a single-loop or series system before it returns to the boiler as much cooler water (which is then reheated and redistributed). The longer the water stays in the system before returning to the boiler, the cooler it gets, meaning that as the water reaches the last radiator/baseboard (or emitter) on its route, it is not nearly as warm as when it reached the emitter.
If your space requires multiple emitters, consider using what is called a one-pipe system. This uses tees to divert water into each emitter along the way, allowing you to control each emitter separately. (The hot water may, for example, skip the first emitter and travel directly to the second if you turn "off" the first.)
Contact a radiant floor heating company and give them your building dimensions, heating requirements and water source location. They can help you decide if radiant floor heat is right for your situation.
A wood stove can warm your building if a chimney already exists or if installing one is economically viable.
Consult a wood heat retailer for advice about which stove is best for your building. Because they are familiar with a variety of stoves, they can help you find the best stove to match your heating requirements.
Locate the stove in the center of the main room (assuming the building has more than one) and run the flue pipe straight up, directly into the chimney, for the best performance and fewest maintenance requirements.
Supplement the heat generated from the wood stove with small space heaters if your building is divided into many small rooms.