i got a few tips to avoid thermal detection.

1. centralize the grow area. put it as close to the centre of your house as possible. the further away from walls the less chance heat will leak out.

2. get as close ,or below, to ground leval as possible. the more house above your heat souce the better.

both do one thing put as much barrier between the heat source and the outside walls of the house. think about it its much easier to see an attic grow room than a basement grow when flying over with thermal imaging equipment.

3. insulate. this is also kinda the same principal as above but the better insulated the house the less heat the house losses making the whole house appear the same basic temp all over.

contrary to popular beleif thermals cannot see "through" walls but can detect hot spots. the idea is to diipate the heat into the rest of the house as quickly as posible.

4. mimic natural light cycles. have your day cycle running when the sun is up and the light out at night. most thermal imaging is done at night so the surrounding area is cooler making it easier to see the hot spots. if they are flying over at 2 or 3 am even in the dead of winter in minasota you can set setyour light to bring on the night cycle before then. wich means that if your lights are off they aint producing heat wich aint makin hot spots.

basicaly just use a little comonsense and planning on the location of a grow as much as any other part of it.