Have a look at these stores they might have a heater suitable. I know the XS cargo store did have an outdoor electric patio heater (rain proof), but it didn't have a thermostat control. It would need an external thermostat switch. Those tropicals will need to be kept around or above 10C, which is difficult. http://www.tscstores.com/pages/locations/allhome/storelocation-home.php http://www.princessauto.com/PAcountry.cfm?CTRY=CAN&INF=loc&SPC=1 http://www.shopxscargo.com/store_locator/default.asp

Don't know about electric heaters other than "when you heat with electric, you have probably chosen the most expensive way". However, do have and use a propane heater here in Wisconsin. If you leave it set for any time at all, without use, Spiders will invade the orifices that control the gas and it is a big pain in the orifice to get it out. Can't be lit till you do. Unit is made by Uniflame Corp with product name "Endless Summer"

I would suggest for a future system that in-floor hydronic heating imbedded in a concrete slab might be a good solution. It’s energy efficient, low temperature and safe for animals and people. Can be fed by an electric or gas boiler. Perfect where doors are opened a lot. This is often used in garages and airplane hangers as recovery time is swift and you only have to be concerned about the temperature between the floor and the height of the dogs. Radiant heat is very comfortable. Just food for thought… IMPO SR

I agree that electric tankless for this use could be appropriate. Here's the thing to know: There is no magic. The amount of throughput (GPM) is math - and is entirely governed by the amount of current it draws. Nobody has any design that gets more GPM for less current. Here's another tip: You may have 200 amp service (meaning the breaker and such) - but I've seen plenty of times, particularly in rural areas, where the lines going to the structure from the utility were way undersized and no-way would they sustain the 80% of the service rating. I think the 27 is the size you would want. A shower is considered 2.5 gpm. Given your deep well, you would likely be able to run your shower with a little left over. You can eliminate some guesswork if you actually measure the temp of the water. Of course a small tank heater would solve a lot of issues, but I understand you don't want that.