Installing an outdoor, wood- or coal-fired oven does not have to be expensive or a tough project, and it does increase your home value. Such an oven requires no gas or electricity to operate, and if insulated will hold cooking heat for 10 hours. Plus, with a little fire it can become a huge capacity smoker. In all, outdoor ovens are considered to be the most efficient option for extended cooking operations.
If ample wood supply is available, an outdoor oven can cook continuously for an indefinite period without maintenance other than ash removal, done while hot. Such an oven does not have to be wood — middle-eastern countries fire their ovens with dried camel dung (no, it does not make the bread taste like crap). Wood-fired ovens have top temperatures that reach 1000 degrees, and they hold in heat far after the fire has gone out (temps drop about 75 degrees per hour). With a door in place, a oven will still be a hot temperature of 400-500 degrees six hours after the fire is out, and still in 200-250 range another three hours later.
The Roundboy oven that I reviewed only cost $1850 as tested, and was quick two hours DIY setup with two people. The best part was that we were cooking pizzas in it that evening because we did not have to wait for mortar to dry.