TerryE Posted December 9, 2017 Share Posted December 9, 2017 @Ferdinand, I wasn't being sarcastic. My point was that dehumidifiers (as in this case) take X kWh to condense out humidity into water and in doing so release 3X kWh of heat into the environment -- plus the X kHr which also ends up as waste heat, so 1X in and 4X out. Link to comment Share on other sites More sharing options...
Stones Posted December 9, 2017 Share Posted December 9, 2017 @AliG Apologies, missed this earlier. As you know we built with ICF. Prior to the decorator coming to tape and fill the walls, we ran two industrial dehumidifiers 24/7 for two weeks (they used 1kW each so not cheap), dropping down to one overnight whilst the taping and decorating was being done. We had them plumbed directly into the drains so no idea how much moisture was actually drawn off, but you could feel the humidity gradually drop and the house feeling warmer and drier. When we got the UFH up and running after I had finished decorating, we set it for an internal temp of 16C, it only took a couple of days to stabilise and sat at that temp until the day before we moved in when I raised it to 21C, which it did over the following 24 hours. Best advice / course of action - dehumidifiers. Link to comment Share on other sites More sharing options...
AliG Posted December 10, 2017 Author Share Posted December 10, 2017 Thanks. Will speak to builder re dehumidifiers today. He was talking about getting some in. I hadn’t thought about the aspect of them warming the place up also. Link to comment Share on other sites More sharing options...
Ferdinand Posted December 10, 2017 Share Posted December 10, 2017 (edited) 11 hours ago, TerryE said: @Ferdinand, I wasn't being sarcastic. My point was that dehumidifiers (as in this case) take X kWh to condense out humidity into water and in doing so release 3X kWh of heat into the environment -- plus the X kHr which also ends up as waste heat, so 1X in and 4X out. Thanks for clarifying, @TerryE. TBH I wasn't sure - I have never thought about the CoP of dehumidifiers. Usually there are other criteria that dwarf the importance of the cost of running dehumidifiers (eg on my only serious rental water leak the tenant had to move out for 2 months, and the Dehumidifier hire cost would be 10+ times the running cost). My evaluation of DHs has revolved around reservoir capacity, the ability to put it on a box and have a hose into a big bucket or drain so I can leave it safely overnight, the existence of a humidistat, and - as usual for me - a slightly anal focus on price when the essentials are met. It was only talking to professional building-dryers that made me internalise the huge benefit of also running extra heaters, even at ££ per hour. Hence the fan heaters while drying the Little Brown Bungalow plaster skim for the sparky who was due 4 days later. In this case, the figures for that DH are: Quote Details The Broughton CR40 dehumidifier is ideal for use during construction and finishing on buidling sites. It is also useful for restoration work after fire or flood damage. It can help control condensation in homes and offices. As the CR40 is a heavy duty unit it is suitable for most industrial and commercial applications. UK Manufactured 2 Year Warranty Extraction 11.25L/24hrs @ 70%RH/20 C 38.01L/24hrs @ 100%RH/35 C Supply 110v or 230v/50Hz/1ph (Dual voltage model available) Nominal Running Current 1.3A (230v) Dimensions 545x370x320 Weight 23kg Based on your number of 4.1 at 100%RH and 35C, that suggests that the CoP at 70%RH and 20C is around 1.2. That highlights how quickly the performance rolls off with lower temp / humidity. Ferdinand Edited December 10, 2017 by Ferdinand Link to comment Share on other sites More sharing options...
Ferdinand Posted December 10, 2017 Share Posted December 10, 2017 (edited) 2 hours ago, AliG said: Thanks. Will speak to builder re dehumidifiers today. He was talking about getting some in. I hadn’t thought about the aspect of them warming the place up also. @AliG Do take a serious look at the costs of buy/sell too. I only ever did one serious "hire-dehumidifiers" exercise, when a T went on holiday in winter and the water froze in the roof leaked. That ended up with an 8k insurance claim, the T back with his dad for 8 weeks, and the house taking several weeks to dry. It was within spitting distance of the new cost of the dehumidifiers used in hire charges. As I put on here this summer, I have now bought a couple of heavy-duty ones. Ferdinand Edited December 10, 2017 by Ferdinand Link to comment Share on other sites More sharing options...
AliG Posted December 10, 2017 Author Share Posted December 10, 2017 (edited) Good news when I was up there today. We have run through another 2 bottles of gas! They have 2 dehumidifiers in the kitchen, but they weren't able to run them and the heating at the same time as it put too much strain on the site supply. So the UFH had been on since Friday, it was -6 outside when I got up this morning. This is much colder than normal. It was 12 degrees in the kitchen and 15 in an upstairs bedroom with humidity in both in the 40s. I told them just to keep the dehumidifiers on in the kitchen until tomorrow so it is warm. They will start putting the kitchen in tomorrow or Tuesday. Tomorrow we can get the mains gas connect up as they put the meter in last thing on Friday. The front door is in and looking good, it just wasn't sealed up around the edges so they had covered it up with cardboard hence I thought it wasn't in. There are still a good few holes such as where window sills are to go in and around the front door. As these get sealed up it will get warmer. I can already feel the benefit of the triple glazing, you could not feel how cold it is outside standing right next to the windows. The current temperature is -2. There was ice on the outside of the windows. I am pretty hopeful we will get in at the end of next week as planned. Edited December 10, 2017 by AliG Link to comment Share on other sites More sharing options...
ProDave Posted December 10, 2017 Share Posted December 10, 2017 We have ice on the outside of the north facing 3g windows, The sun melted the ice on the south facing ones today. Mid day high here -5 We tried the dehumidifier in the 'van today and it barely removed drop of water. I guess that's because it's too cold for there to be much moisture in the air? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted December 10, 2017 Share Posted December 10, 2017 (edited) 6 minutes ago, ProDave said: We tried the dehumidifier in the 'van today and it barely removed drop of water. I guess that's because it's too cold for there to be much moisture in the air? Very likely. With temperatures as low as you've been having the air is going to be pretty dry by now, and one snag with the caravan being so cold, and probablyu not very airtight either, is that the humidity level inside it probably isn't getting very high, either. Edited December 10, 2017 by JSHarris Link to comment Share on other sites More sharing options...
Nickfromwales Posted December 10, 2017 Share Posted December 10, 2017 2 hours ago, AliG said: Good news when I was up there today. We have run through another 2 bottles of gas! Link to comment Share on other sites More sharing options...
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