You need an automatic backup heating system for several reasons:

1) you may in fact find that it is not practical to use the alternative heat source year round, for the
amount that you may save during the summer months when you need very little heat, compared
to the cost of operating a conventional sytem (unless you have a huge summer heating demand,
such as a swimming pool, etc). Use this time to stock up your alternative fuel supply.

2) you will need a backup heating system for those cool days we have once and a while,
if the alternative heat source is shut down and of coarse a backup for domestic hot water.

3) should you get hurt and be unable to handle the operational of the alternative heat source.

4) should you wish go on an holiday it may not be convenient to find and train someone to
operate and check on the alternative heat source for you.

5) should the alternative heat source fail to produce heat while you are away
(ie: pump fails, no fuel, fuse blows, shear pin fails, etc.).

6) should you be away (at work, day trip, etc.) and unable to get back in time to load
the alternative heat source before it runs out of fuel.

7) should the alternative heat source be out of commission for a period of time.

8) Your insurance company will usually require a back up heat system to the alternative
heat source in order provide you with a insurance policy that covers freezing.

For existing buildings, the existing heating system is left in place unchanged, as an
automatic back up and for new construction a new furnace, boiler or electric baseboard heat
could be installed for a backup heat system. This is accomplished quite simply, as separate
thermostats or controls are installed for both the alternative heat source and backup heating system.