D4D E27 Heater Loading when cold

[greyskull2]

Hi, would anyone else have noticed that their idle revs increase substantially when the engine is cold and they put the heating/venting system on? My revs double at idle as if there is a huge loading being applied. I can't replicate it even if I put every other bit of electrical kit on at full load (all lamps, all wipers, rear window heater, hazards, stereo, etc) D4d, 2 litre, E27 estate, 2010 model? Thanks

[Konrad C]

I would say it is normal for various reasons regardless of the engine, even though I own the valvematic petrol variant. You didn't mention if you set the heating/ventilation (HVAC) to demist the windscreen, because this uses the AC which is a big power drain. On the diesel variant, it has dual radiator fans (petrol only has one), the heater fan. Also the AC compressor is another load. Add the fact the engine has just started, so needs to warm up, the Battery needs recovery recharge, meaning the alternator load is high. Once the engine has warmed up, the engine settles down to a lower idle speed. 
My valvematic has really high idle speed for the first minute or so, but drops quickly if driven and not left standing.