tmdgts Posted March 7, 2018 Share Posted March 7, 2018 We have been told recently by a dealer that if we opted to remove the Omnivent 3 speed roof fan fitted in the ceiling area in the kitchen replacing it with a roof air conditioning unit, whether this be Dometic, Truma, Kronings, Houghton.. we would require additional ventilation! (this is to be installed into a new motorhome) the guy was quite clear even when questioned. We then checked with another dealer and were told this was not the case and we would not need any additional ventilation, who is right? Thanks. Link to comment Share on other sites More sharing options...
StuartO Posted March 7, 2018 Share Posted March 7, 2018 tmdgts - 2018-03-08 4:27 AMWe have been told recently by a dealer that if we opted to remove the Omnivent 3 speed roof fan fitted in the ceiling area in the kitchen replacing it with a roof air conditioning unit, whether this be Dometic, Truma, Kronings, Houghton.. we would require additional ventilation! (this is to be installed into a new motorhome) the guy was quite clear even when questioned. We then checked with another dealer and were told this was not the case and we would not need any additional ventilation, who is right?Thanks. Roof air conditioning recycles the air inside the MH and does not draw in or ehaust any air through the roof, so replacing an existing roof vent with air-con unit would reduce the available ventilation. Whether that is a critical reduction (eg for purposes of using a cooker beow it) might depend on the design of the particular motorhome (eg whether there are other roof vents or windows can be opened) but it doesn't sound very likely. We have roof air-con and it has occasionally been useful when on a site (and on EHU) in a hot country but it's too noisy to use overnight and we manage well enough with fans when necessary. Overall I regard roof air-con as more trouble (and weight) than it's worth and would not specify it again. Link to comment Share on other sites More sharing options...
aandncaravan Posted March 7, 2018 Share Posted March 7, 2018 I agree with Stuart. You would lose some 'ventilation', as defined by "a loss of fresh air entering the vehicle to replace air going out the Omnivent", but whether that would need to be addressed is anyone's guess. Maybe the Dealer is thinking that fitting the Aircon would result in all the windows being closed for more of the time for maximum efficiency, as you do on a car, so that condensation becomes more of an issue. Unlikely though, as Aircon 'drys' air so removing the need to expel the moisture laden air. Most Motorhome owners are aware of the need for ventilation, especially when cooking, that I would assume most would be sensible enough to open a window when required? Also agree with Stuart on the value of it, only usable on EHU, so no value when Free Camping, travelling, etc. and too noisy at night. Link to comment Share on other sites More sharing options...
Charles Posted March 7, 2018 Share Posted March 7, 2018 Sounds like he wants to sell you a fan as well. When the air con is on you close the windows anyway. You wouldn't buy a fridge and leave the door open, as we used to say :-D Link to comment Share on other sites More sharing options...
PJay Posted March 7, 2018 Share Posted March 7, 2018 We had roof air con fitted when our van was new. Would not waste your money on it. Apart from the extra weight added, (Heavy) we seldom used it, even in Spain ! We eventually took it off , as we had a weight problem, and sold it on ebay.Had little use in 10 years ! We had a roof light, as well as the aircon. When we took out he aircon put another roof light in place Don't waste your money!! PJay PS if you find you NEED it (and it is noisy ) can always be added later! Link to comment Share on other sites More sharing options...
tmdgts Posted March 7, 2018 Author Share Posted March 7, 2018 The technician who fits the units indicated it was something to do with H&S as though there was some kind of regulation which is really why I posed the question here. As far as air con is concerned this is something I am wanting to have the dealer has had no input other than suggesting Dometic was not all that great. It is interesting the fors and against air con. Thanks for your comments. Link to comment Share on other sites More sharing options...
Charles Posted March 7, 2018 Share Posted March 7, 2018 You need a % fresh air in on buildings that occupy more than a certain number of people when installing big ducted systems, can't remember the numbers. Can't imagine it being law on a motorhome with 2 people in it, that would be bonkers, cars are smaller spaces and can have 5 people in them, never seen a roof fan on a car lol. Link to comment Share on other sites More sharing options...
StuartO Posted March 7, 2018 Share Posted March 7, 2018 tmdgts - 2018-03-08 6:29 AMThe technician who fits the units indicated it was something to do with H&S as though there was some kind of regulation which is really why I posed the question here. As far as air con is concerned this is something I am wanting to have the dealer has had no input other than suggesting Dometic was not all that great. It is interesting the fors and against air con. Thanks for your comments. Clearly you could ask this technician to explain what the H&S consideration is and in particular if there is a specific requirement, what it is. One hears a lot of rubbish spoken about H&S requirements these days, so until you get chapter and verse I wouldn't assume this advice you had is soundly based. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 7, 2018 Share Posted March 7, 2018 In a 2010 forum discussion about motorhome rooflight ventilation I commented "I believe there are guidelines - or perhaps even regulations - defining the amount of permanent ventilation a leisure-vehicle should have, and I vaguely recall seeing some figures, based (if I remember correctly) on the size of the vehicle's living area, in an older CAK brochure. Presumably such 'rules' go back to when open-flame heaters were used in leisure vehicles and may well link to domestic building regulations.” I also recall a conversation at Brownhills in 2004 with a couple that had purchased a new large Auto-Trail motorhome. Having complained that the vehicle was horribly draughty and discovered that its several rooflighhts were all the ‘permanent ventilation’ type with just one rubber seal fitted, they had asked if additional seals could be added to reduce the amount of wind blowing through the rooflights. They were told that this would be permissible, but only if extra rooflights were installed. Link to comment Share on other sites More sharing options...
crocs Posted March 7, 2018 Share Posted March 7, 2018 Sounds like a technician who has perhaps conflated more than one issue and reached a conclusion that he thinks is correct. I agree that he should simply be asked to prove his assertion. I’m a fan of aircon and had it on all my motorhomes, twice by replacing an omnivent (!). They’ve all been Dometic and I’ve been very happy with them. But worth considering Truma if you have Truma heating as the aircon controls can be linked with the heating control panel and the remote control can operate both systems. Link to comment Share on other sites More sharing options...
tmdgts Posted March 8, 2018 Author Share Posted March 8, 2018 It appears Derek you have touched upon something that just might be where this technician is coming from and I am wondering if this is why he is stating what he has about ventilation, he works on statics, caravans, motorhomes and rented vehicles: BS EN 721:2004 Leisure accommodation vehicles - Safety ventilation requirements. Mentioned in the HSE document: Gas safety in caravans, including leisure accommodation vehicles and residential park-homes http://www.hse.gov.uk/foi/internalops/ocs/400-499/440_34.htm Link to comment Share on other sites More sharing options...
tmdgts Posted March 8, 2018 Author Share Posted March 8, 2018 In addition: Swift Group says the following in the 2018 Owner’s Handbook Coach built motorhomes: Ventilation All motorhomes comply with BS EN 721. The ventilation points on your motorhome are fixed points of ventilation which are required by the European Standards. All motorhomes have ventilation at high level and low level which have been calculated to suit the individual needs of your motorhome. High level ventilation is achieved by means of the roof lights and washroom roof ventilators (where applicable). The low level ventilators are positioned under sink units. Under no circumstances must these vents be blocked or obstructed in any manner as this could lead to insufficient fresh air. In this case the confined atmosphere becomes depleted of oxygen which could lead to dangerous levels of carbon dioxide (CO2 ) build up leading to the risk of asphyxiation. The risks of carbon monoxide (CO) build up, which is a colourless, odourless and tasteless gas, will also be reduced with ventilation. Carbon monoxide is produced from incomplete combustion and should the CO detector be activated the cause of the incomplete combustion must be investigated prior to reusing the appliance in question. It is advised that fixed ventilation points are checked and cleaned (if necessary) on a regular basis using a small brush and a domestic vacuum cleaner. Additional night time ventilation is obtained by releasing the window catches and placing them in the second groove. Note the windows are not sealed from rain in this position. As the ventilation levels are calculated to suit each model requirements no modifications should be made which may result in reduced ventilation levels. On a thread on practical caravan one person has posted: BS/EN721/1999 as ammended 2004,(Leisure Accommodation Vehicles Safety Ventilation Requirements), states; minimum low level ventilation for vans in this case with 5 to 10 square metres of floor space is 1500sq mm or in real terms an opening of 100x15mm which is but a fraction of the standard door vents capacity. High level ventilation requires more and in this case it is 10,000sq mm which should be taken care of by the permanent ventilation of one closed rooflight which is of the order of 12000mm square even with the blind shut. https://www.practicalcaravan.com/forum/general/1203-floor-vents Link to comment Share on other sites More sharing options...
tmdgts Posted March 8, 2018 Author Share Posted March 8, 2018 UPDATE: Further to my message yesterday to the forum about Air Con units and Ventilation: I have just received confirmation from Swift Group direct after I contacted them earlier today and they have categorically confirmed that should we fit a air conditioning unit in our new motorhome replacing the Omnivent that comes as standard in the new motorhome then we WILL require additional ventilation because the vehicle will no longer conform with BS EN 721 Safety ventilation requirements and we would be required to add an additional 15,000 mm2 to bring this back to requirement for this vehicle. The length of motorhome in question is 7.09m / 23'3" I was advised the technical team at Swift Group should be contacted by dealers to ensure the fitting of any additional dealer fit options that affect ventilation needs to be checked out because they may have on the warranty of the motorhome and the same should any customers wish to fit anything themselves that may effect ventilation. So amazingly we have one dealer who is correct and another one who is not how many more out there will continue to fit air con units and not realise they are affecting your warranty, I was told this something that has not been raised with Swift before by a customer... Thank you Derek for spurring me out to check out the facts! tmdgts - 2018-03-07 1:27 PM We have been told recently by a dealer that if we opted to remove the Omnivent 3 speed roof fan fitted in the ceiling area in the kitchen replacing it with a roof air conditioning unit, whether this be Dometic, Truma, Kronings, Houghton.. we would require additional ventilation! (this is to be installed into a new motorhome) the guy was quite clear even when questioned. We then checked with another dealer and were told this was not the case and we would not need any additional ventilation, who is right? Thanks. Link to comment Share on other sites More sharing options...
PJay Posted March 8, 2018 Share Posted March 8, 2018 tmdgts - 2018-03-08 4:54 PM UPDATE: Further to my message yesterday to the forum about Air Con units and Ventilation: I have just received confirmation from Swift Group direct after I contacted them earlier today and they have categorically confirmed that should we fit a air conditioning unit in our new motorhome replacing the Omnivent that comes as standard in the new motorhome then we WILL require additional ventilation because the vehicle will no longer conform with BS EN 721 Safety ventilation requirements and we would be required to add an additional 15,000 mm2 to bring this back to requirement for this vehicle. The length of motorhome in question is 7.09m / 23'3" I was advised the technical team at Swift Group should be contacted by dealers to ensure the fitting of any additional dealer fit options that affect ventilation needs to be checked out because they may have on the warranty of the motorhome and the same should any customers wish to fit anything themselves that may effect ventilation. So amazingly we have one dealer who is correct and another one who is not how many more out there will continue to fit air con units and not realise they are affecting your warranty, I was told this something that has not been raised with Swift before by a customer... Thank you Derek for spurring me out to check out the facts! tmdgts - 2018-03-07 1:27 PM We have been told recently by a dealer that if we opted to remove the Omnivent 3 speed roof fan fitted in the ceiling area in the kitchen replacing it with a roof air conditioning unit, whether this be Dometic, Truma, Kronings, Houghton.. we would require additional ventilation! (this is to be installed into a new motorhome) the guy was quite clear even when questioned. We then checked with another dealer and were told this was not the case and we would not need any additional ventilation, who is right? Thanks. Depends where the Air con is fitted. Ours was fitted behind the Heki roof light towards the back of v an So did not need another vent. I suppose the layout of the van depends on the placement of the air con. When We sold ours , the guy who bought it , had an 8 mtr van, so was going to fit over the rear bed., as that is where he said he needed it, we have found that a elec fan serves our purpose , and is cheaper and lighter, as i imagine you would need to be on hook up , or running the engine to use it? PJay Link to comment Share on other sites More sharing options...
Archiesgrandad Posted March 8, 2018 Share Posted March 8, 2018 I removed the roof aircon from our last van, and weighed it, 85 Kilos with all the gear. I did have a Kontiki which had an aircon unit fitted under one of the settees, it was much quieter, just as effective, and whatever it weighed it was much lower down. AGD Link to comment Share on other sites More sharing options...
bazooka Posted March 8, 2018 Share Posted March 8, 2018 I also agree with stuarts cmments Link to comment Share on other sites More sharing options...
aandncaravan Posted March 8, 2018 Share Posted March 8, 2018 You may already have enough ventilation as a single 14" x 14" Roof vent can exceed the BS EN 721 specifications on it's own with up to 22,000mm3 air flow, see below. Even an ordinary old school MBK style 280mm x 280mm (about 12inches square) has an airflow of 5,400mm3. EN 271 allegedly states that a vehicle needs a specific air flow dependent on it's floor area. For larger caravans/motorhomes of 10 to 15msq floor area = 12,500mm3 high (roof level ventilation) and 2,000mm3 low level ventilation. 15 to 20msq floor area = 15000 high and 3000 low respectively. The below specifications of a couple of roof vents showed the Euro vent has a flow rate of 22,000mm3 on it's own, so depending on what you already have in the Shower room, etc might mean you don't need anything else? Is it worth calculating what your existing roof vents are actually rated at, assuming you have more than one? Examples : INTEGRATED ROOF VENTS SKY LIGHT 280 x 280 mm CARAVAN MOTORHOME Strong double skin dome for constant free airflow, spacers in between skins prevent deformation and restriction of airflow. Free airflow to European spec 5400mm3 even with dome closed. EURO VENT ROOF LIGHT ASSEMBLY Complete windup euro vent roof light assembly with removable fly screen. Self venting ventilation rating 22,000mm3 SIZE; 14 x 14 x 4 deep liner https://www.novaleisure.com/store/category/856/product/d39.aspx Even if you do need to do something, replacing an existing roof light (or fitting new) with something similar to the 14" square Euro Vent doesn't sound difficult or expensive? Please don't rely on my figures alone, suggest you do your own searches? Link to comment Share on other sites More sharing options...
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