sweettooth Posted August 4, 2022 Share Posted August 4, 2022 I'm really sold on the idea of inline duct heaters now. As @ratdog has pointed out several times, drying the incoming air (should help with my RH issues), avoiding dew point on lights out (really important to avoid rot) and hopefully a lot cheaper to run than my 1.5kw heater. Been looking on ventalationland. My outtake is soon to be 10" so could I get away with a 5" 300w unit? 300w is the same as my towel radiator which Im happy to keave on 24hr a day. if not than it will have to be the larger 6" 500W unit. If I choose the 6", I would move my current 6" hyper fan to the intake, going 5" would require a new fan but hyper van now do 5" fans so can stay the ec route. Either one will be rigged up to an inkbird itc308 or is there a better thermostat for these duct heaters? Is there also a minimum flow rate required for the heaters, I guess using smaller active intake would be running at a higher cfm flow so shouldn't be an issue, my fan controller can manage negative pressure requirements and balance the fans. Link to comment Share on other sites More sharing options...
MindSoup Posted August 4, 2022 Share Posted August 4, 2022 Not too clued up on duct heaters but when I can get a bigger setup its what I'll be using. So if you don't mind I'll pull up a chair and take some notes. 2 Link to comment Share on other sites More sharing options...
sweettooth Posted August 4, 2022 Author Share Posted August 4, 2022 Some maths based ramblings...... Due to my room size and the flow rate of my 10" (1787m3/h) I think it'll be the 6 inch. Minus 25% off the extraction for filter and ducting gives me 1341m3/hr. The 6" I have is 560m3/hr. Factor in the negative offset of the controller, I think the 5" would be too small as it only pushes 350m3/hr. I could use 6" to 5" reducers and use the smaller 125mm 300W heater with a 6" fan but I think i would only be reducing my airflow too much. At current elec prices, 24 hours at 300w is about £2.08 a day. 500w takes it up to £3.48, quite a difference over the month although shouldn't really be used much when lights are on. I think I'm swayed for the 150mm 500w unit. Link to comment Share on other sites More sharing options...
ratdog Posted August 5, 2022 Share Posted August 5, 2022 if your room is big enough to accommodate a 10" extract, the 300 will be too small mate Link to comment Share on other sites More sharing options...
OddNut Posted August 5, 2022 Share Posted August 5, 2022 Metal duct and heater after your fans. Also I’d put somthing filtery before the lot just to stop anything getting through onto the element 2 Link to comment Share on other sites More sharing options...
Devon Cream Posted August 5, 2022 Share Posted August 5, 2022 If your going to a 10” outtake I’d be going for a 8” intake. Link to comment Share on other sites More sharing options...
ratdog Posted August 5, 2022 Share Posted August 5, 2022 25 minutes ago, Devon Cream said: 8” intake. that's going to be one hell of a duct heater, about £180 but still worth it imo 1 Link to comment Share on other sites More sharing options...
Devon Cream Posted August 5, 2022 Share Posted August 5, 2022 48 minutes ago, ratdog said: that's going to be one hell of a duct heater, about £180 but still worth it imo I wasn’t on about the heater just on the fact I’d be using a 2 inch difference between the 10” extraction outtake and the intake size. Link to comment Share on other sites More sharing options...
ratdog Posted August 5, 2022 Share Posted August 5, 2022 42 minutes ago, Devon Cream said: I wasn’t on about the heater i know, that's why i said it's still worth getting the heater as well i should have just posted instead of quoting 1 Link to comment Share on other sites More sharing options...
OddNut Posted August 5, 2022 Share Posted August 5, 2022 I’m in the market for a duct heater too an 8” one but it needs to be under 2000w to run of my gas enviro controller .. systemair do one around that wattage. Im hoping that it won’t be needed so much with the underfloor heating I’ve put in but we will see 1 Link to comment Share on other sites More sharing options...
MindSoup Posted August 5, 2022 Share Posted August 5, 2022 I like the look of the Blauberg 1.2kw 150mm units, they're cheap and have a 5 year warranty. I've had one of their little ducto 100s on my veg box for about 2 years and it's still good as new. 1 Link to comment Share on other sites More sharing options...
sweettooth Posted August 9, 2022 Author Share Posted August 9, 2022 I can get a 500w 200mm heater but would need a new 8" fan for the intake, plus a silenced ec one so pushing nearly 350 notes or higher if I want to match the systemair vector v2 I have, that's near on 500! would a 6 inch active heater intake plus additional passive intakes work or would I be drawing in too much unheated air and defeating the point in the first place and use more electricity in the long run? Link to comment Share on other sites More sharing options...
MindSoup Posted August 9, 2022 Share Posted August 9, 2022 It would probably still keep the tent warm, but I imagine it could have quite an impact on the efficiency. Link to comment Share on other sites More sharing options...
ratdog Posted August 9, 2022 Share Posted August 9, 2022 1 hour ago, sweettooth said: and use more electricity in the long run? you wouldn't be using more electric as the duct heater will be on constant, it's not thermostat controlled, just an auto cut out i should imagine, i would try it, might not need to have more than the one 6" intake in winter, the 10" will be only ticking over won't it? and extracting on lower settings i would expect?, it's not like you are going to have the crazy temps we have now. 1 Link to comment Share on other sites More sharing options...
sweettooth Posted September 25, 2022 Author Share Posted September 25, 2022 sticking with my 6" out for now and will rob the 6" from the veg tent which means I will need the 150mm 500w version. don't think the inkbirds are the best to control these and should be going with the recommended controller from the accessories section, question is the cheaper gas chamber thermostat or the more expensive one with a 60 second cycle..... buy cheap buy twice, the more expensive unit looks like it will pulse the heat on and off to maintain the temps so theoretically over a 24 hour period of switching say 30 on 30 off, that's only 250w over the 24 hour period, much cheaper than larger oil rads and fan heaters. colder mornings are creeping in and I'm not running a 1500w heater inside the tent anymore 2 Link to comment Share on other sites More sharing options...
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