Usually the answer is sure, BUT because PV is so expensive, what you are now accomplishing is taking all the electricity that you just paid a premium for, and using it to waste in an electric heating element, when it could be used for running appliances. My detailed answer to them is there are much more cost efficient and cost effective ways to get heat energy. But IF you didnt pay anything for your PV modules or maybe paid very little, OR you have the PV modules sitting around doing nothing, it might be to your advantage to use it for heat.