Alternatives to Large Transformer or PSU for Driving DC Heater
They tend to use long quartz tungsten heaters for SMD reflow.

But you can use an industrial power 10kW dimmer and Halogen flood lamps positioned for forced air recycling as well as radiant heat. Some trial and error or review of existing commercial solutions is needed.

Then you can use multiple temp zone sensors top, bottom, centre, with exhaust air vented safely, forced air circulated inside and room humidity raised towards 50%. Each of these variables will affect final results along with your thermal profile for preheating ramp, solvent evaporation, liquidus duration and ramp down according to datasheet specs and solder+paste used.

High Temp Insulation will help reduce the room temp. if you can do this.