Maybe not but I would.

As long as it's a good quality detector and there are no temperature fluctuations or draughts then a PIR would be OK, however for the difference I would use a DT.

Thanks chaps - I was going to go for the Texecom mirrored quad @ £13 - the DT's appear to be more than double. No issue in paying the extra if it's worth it - I didn't know if the likelyhood of a fault is a lot higher for a quad or not... 

 

I'm also going to have to solder a few wires if utilising the existing cabling - going to solder and heatshrink, any tips before i start.... Gather I would need to test resistance afterwards?

You can always go the cheaper option but it's you that will be attending the false alarms.

Fair comment  

 

The reason for the question was that in reading, DT's for garages appear to be needed for wind/sudden temp changes/rodents & spiders - so with my garage being largely sealed, I wouldn't have thought it was required, but i suppose where your coming from is - better be safe given the menial extra cost

It would cost more to return and replace than fitting one in the first place.

Any garage with a traditional uninsulated up-and-over garage door should not be considered 'sealed'.

 

If the sensor is to be hard wired (assume it will be one of the few detectors within reach of the panel) then, yes, it should be a DT.

That's sealed it then - DT it is ....this one will be hard wired facing the door itself, but into the back of the remote panel which will be in the hallway, mounted on the garage wall. 

Always best to face a DT into the property and make sure you adjust the MW range correctly.

I remember K band military being a revelation .