Totally makes sense and I especially agree with the insulation through brick walls (including internal ones). This truly cannot be said enough and yet heating engineers leave pipes unprotected laying gains masonry all the time ... My one and only addition is that in certain cases, when a pipe is enclosed in a service cavity i.e. under your floor and the house has sufficient insulation (sound or thermal) you absolutely want to insulate the pipe. The reason is not thermal performance but rather protecting the building materials and your floor coverings. You can raise the temperature of an enclosed cavity to a point when it's drying up timber too much and in essence create a hot pocket. Your flooring and other timber materials can warp because of the lower humidity level at that location compare to the rest of the floor. All of this is easily avoidable by insulating the pipework in cases where you might be creating a localised "heat chamber". On and this does not apply to 15mm pipework. There's usually not enough heat from them to cause issues like this.

I agree. I guess that's a reason why we run heating pipework through the hallway as a type of underfloor heating. The heat is better and more evenly spread throughout the room rather than be co centrated in one location too

In the UK, if you read the Part L building regs, you'll find the need to insulate any exposed pipes, including those in voids; inside the 'thermal envalope' - granted thats for new builds though

After watching a previous heatgeek video, I insulated all the exposed pipes immediately between my boiler and the void in the ceiling where the pipes went off to feed the house . This area has a radiator in the near vicinity and so I would argue the loss of exposed pipes was irrelevant in that area. Anyway, the efficiency of my boiler has increased and I've been able to drop my flow temperature down from 65 to 60 degrees even in the recent cold patch. However, watching this has helped me decide not to bother insulating any more of the remaining pipes in voids etc. (I think!) It's never b & w is it!!

I've always wondered about this in floor spaces and have yet to do it. I was considering starting to do it with heat pump installs so I'm glad you've cleared this up.

Trying to explain this to building control after the Part L changes is not fun as they practically insist at times that anything not a radiator should be lagged. Next time I get a difficult one I'll send them to this video, it's faster than digging out the literature.

Makes sense. Says me after fully lagging. I had a memory where you said to lag the pipes - 28mm pipe work video. With that in mind lagging was a better option, for me. Or, how wrong am I? - could have used bigger pipes for all the effort!

Makes worlds of sense not spending extra money on unneeded instulation, or hacking away at the building fabric to reach it.

Really looking forward to your balancing radiators video. Looking to replace the all the knobs with thermostatic ones. Would you recommend the Heimeier Eclipse system over the normal one?

Unfortunately you do need to zone a house heating because you don't sleep in your living room or spend the day in your bedroom, so these will need different temperatures during the day. And it's not just about the savings in energy but also about comfortable temperatures, and that depends a lot on what you are wearing while in a specific room. So by default is better to insulate all pipes and oversize the radiators.

With hydronic heating in concrete floors it's best to insulate the supply pipe to each manifold and to insulate your domestic hot water piping. I get your rationale for not insulating the piping but I have thermostats in all the zones of my hydronic and want them to control the temperature of each room. In summer my domestic hot water lines are insulated so I don't have to provide more cooling with my air conditioning.

Adam, you have no idea how grateful I am know that I don't have to rip open my ceilings and floors to insulate the heating pipes! (This isn't sarcasm btw)

I think this idea is for a very specific type of installation where there are short runs of well designed and thoughtfully located pipework. In most scenarios all services including hot and cold domestic pipework is run alongside heating. I would suggest that uninsulated htg pipework would risk heating up cws pipework and cause legionella risks even if the cws is lagged. Bear in mind that cold water and chw pipes are at risk of condensating where not correctly vapour-sealed. This situation could be greatly exaggerated in your scenario.

In my case the floor between the ground and 1st floor is not "within the insulation envelope" because I live in a 30's house with a howling gale running between the floors. I also found that the cold water pipes were running alongside the heating pipes, meaning that I had to run the tap for a while to get cold / fresh-tasting water. My rooms are all separately timed / zoned from each other (my heat moves around the house with me, on a schedule) so i feel that insulating the pipes was a good move, overall. It was not expensive and I was pulling the floors up anyway, upgrading the pipework for a possible heat pump installation (on which I am yet to be convinced, though I am still thinking about it).

The heat from boxing in doesn’t just “end up in other areas, as the temperatures equalise”. The boxing is being kept at a toasty 35c, while the room is colder than it would otherwise have been had the pipes been lagged (for the same amount of gas burned)

Similar argument over incandescent light bulbs. Heat and light at the same time. The heat may not be considered efficient as it's not light energy but in the UK, certainly for half the year, needing to use lights and heating go together :)

If there’s a soil stack in the same ‘boxed in space’ as heating pipes, inside the thermal envelope of the house, the soil stack should be insulated, but I wonder how many are? In my case I insulated the soil stack, boxed it in with ply, and ran the heating pipes up the outside, then boxed over them.

Great video, I only lag cold water inside properties so I don't have warmed water when I brush my teeth etc

Very obvious, but very well explained 👍

How long can the external pipework run be or the maximum length before being detrimental to the air source system? Can the external pipework be underground and at what depth should it be placed?

Does a granule burner have the same lower heat setting efficiently inceases?

Midway through a refit in my house and up to this point have pretty much insulated all pipes, I will think twice though when doing the rest. However given that a lot of the electric cables are running in the same voids as the pipes and in some instances the cables cross pipes as they do their merry dance to sockets, I see some benefits of insulating given that I don't want transfer to the cables.

Could you do a video about having pipe clamps above the lagging and below and compare the cop? Mine seem to be clamps under the lagging and i suspect it should be the other way round!

What about for protection against condensation leading to mold in the walls for the refrigerant line when in defrost cycle?

Just subbed, very cool video

Hi, So is there a site or someone who I could go to to get an air source heat pump installed in a first floor flat in Cardiff? I want to be good and get solar and a heat pump, I am just concerned that I will either be sold a pup or overcharged or both.

My cat found where the central heating manifolds were as soon as we moved into the house. Upstairs in two bedrooms. I wondered why the cat lay on the floor. Yes, many people have been doing what you advise for years but I think the large pipes in my airing cupboard could do with insulation although my wife like a warm cupboard in which to store linen and towels. The cylinder is spray insulated foam.

One exception to "not insulating the pipework within the thermal envelope" might be the plant room. In my case, it's a fairly small space (1.5 x 2.5 meters and 2.4 meters high), which we obviously don't live in and which happens to have a lot of pipework between the boiler, the indoor unit of the heat pump, the buffer tank, the expansion vessel, the UFH manifold, and so on. In this very small space, the pipes would emit a lot of heat that isn't really needed there, causing it to overheat. I'd much rather have that heat/energy stay in the water in the pipes so it can be emitted in other parts of my house.

I'm not a heating engineer, and my main concern with NOT insulating inside the thermal envelope, is frozen pipes When it got very cold a couple of weeks ago, my washing machine couldn't drain. Yes, the waste pipe connects into a pipe that's not actually used for heating, however at the same time, other pipes could also freeze. I did notice I had to restart my boiler a couple of times too which *could* be due to frozen pipes too

Doing an install in a basement, haven’t seen an air brick, should I insulate?

Why over heat corridors?

Another reason to insulate cold water pipes is to reduce the risk of condensation forming on it.

My 1947 2 bed bunglow converted into a 4 bed dormer style house has complicated heating pipework runs. As the suspended timber floor is uninsulated my heating pipes should be fully lagged. Where the heating pipework runs under the Kitchen base units is not straightforward? The whole of the ground floor should be thermally insulated including under staircases and underneath kitchen/ bathroom fitings. So a surface run pipe in a void above drafty floorboards, could insulate floor area in void, or insulate pipework can't see much difference. Equally where the heating pipework runs up the partion wall between dwellings. Don't really want to heat up next doors house, but their house is fairly well insulated and can afford the heating! Is therefore best to concentrate on the thermal barriers and heating pipework within the cold unheated spaces.

Should any insulation be added when feed and return manifolds are close together? To prevent the hotter feed tubes warming the cooler return tubes and therefore reducing delta T across the boiler? You could just insulate the feed side?

If you had uninsulated CH pipes under a vented insulated suspended flooring (GF old Victorian ), would that would be considered outside the thermal envelope. Also say you had boiler/cylinder in a small extension room to the kitchen, no 2nd floor above, you may want to insulate the pipes as it would be additional heat loss in the room which already will be warmed from the boiler/cylinder, pump etc that is in that room.

But what happens when I use the air condition function in the summer? Would water droplets forming on all the inside pipework? Good vid though 🙂👍

Guessing you still going to want to insulate your hot water system pipe work to avoid losing unnecessary heat into the envelope during the summer.

Dear heat geek - I would love to hear your opinions on electric radiators, particularly Vs heat pumps, what are the pros and cons and when would one system be better than another. I would also love to hear about low-H2O radiators such as the jaga strada, they supposedly use 90% less water so claim to be more efficient. Would love to hear your thoughts

If I’m running a cold supply within the same boxing as heating pipe work, I’ll insulate both pipes to prevent heat transfer to the cold supply

Your SAP/EPC score will suffer a tiny bit for this. Also if you are running the pump for hot water only during summer wont this contribute to overheating?

Is there an argument for insulating pipework to help radiators/rooms further away on the circuit get warm more quickly? If a disproportionate amount of the uninsulated pipework runs through a particular part of the property, then won’t you get a disproportionate amount of heat coming in to those areas, making the rads further away struggle? I think I have this problem - despite my best attempt to balance the system I have a room at the end of a run that just struggles no matter what. Long exposed pipe runs are nowhere near it even though inside the envelope. Interested to know your thoughts on this. Thanks for your video and looking forward to the vid on balancing.

Need to be aware of thermal bridging between floorspace and exterior walls in some properties, e.g. old stone walled buildings with insulation on wall interiors. Exterior insulation would be better in these cases to better use the thermal mass of the building but not always possible due cosmetic concerns, listed building etc.

I have a new condensing boiler, tanks in the loft and airing cupboard with water cyinder. Should I insulate the pipes in the airing cupboard?

Would you insulate pipework that runs in an internal garage?

I totally agree.... But this is against new building regulations. I think.... 🤣. I've just lagged everything in the last three jobs much to my annoyance.

What’s your opinion on radiator pipework running through screed above a concrete slab, none of which is insulated? Octopus are installing a ASHP and I I can’t get a straight answer on whether the loss of efficiency makes it worthwhile changing the radiator pipework to run up the walls and into the first floor void. My rough calculation is that there’s currently 30 meters of pipe currently running in the screed.

"and lastly, please do always insulate [pipework going through] brick walls". I don't see why you should *always* do that. Depending on the construction style (varies by region/country), brick walls can be used inside the thermal envelope. Why would you insulate those? Other than that, love the video -- makes complete sense!

I've watched many off grid stuff, especially North America. For years on wood stoves. When it comes to chimneys. Now they are making the chimney routes even longer inside the building. If the chimney is still warm, what's the point putting it outside the building. When it could radiate the hear inside. So not insulating pipe works make sense. It's simply making you system bigger.

Some people insulate for fun. A college I went to had the cold water pipes insulated inside the building. Only reason I can think is health and safety insulation is soft but I see no other point to it.

I have a question…..my parents have a detached house with a fairly new Ideal boiler heating 13 not very big rads and a megaflo water cylinder. They had the boiler temp set to 70. When the heating is on the return is about 68 so no condensating going on there. I lowered the boiler temp to 60 which made the return about 53 and with a few tweaks to the rads the house was still warm even in these current very cold conditions. My father is worried about the hot water temp as the cylinder stat is set to 60. What are your thoughts please? By the way, great videos, very interesting.

not a heating engineer but been saying this for years the warm pipes on my landing under the carpet are just acting as extra radiators.

Ima smisla, osim ako kotlovnica ne radi cijelu godinu. Tada je potpuno promašeno ne izolirati cijevi jer će kuća biti pregrijana i toplina će stvarati nepotrebnu potrošnju energije.

Hi, I loved all your videos over the years, Keep up the good work. I have a problem you might be able to help with. I have a Ferroli optimax HE25S gas boiler it’s about 12 years old now. The mother board had a intermittent problem, it would stop for no reason. I’d take it out look at it (no signs of damage) and refit It. It would work for years, I thought it was a cracked PCB. However I ordered a new PCB (DIMS23)for a UK supplier and when I fitted it comes up with an error code F37. No program book came with it and the supplier has no idea. Would you or your contacts know how I can change the program or have a programming book? Many thanks and a happy Christmas to you and your!

As I understand it the new building regulations require pipes to be lagged inside the home

So who has been insulating pipes inside the thermal envelope?

Hi Adam, I highlighted key bullet points to help me understand your video more: - Pipe work within the thermal envelope that only contributes to heating does not need to be insulated - Insulating pipe work that does not contribute to heating within the thermal envelope can increase efficiency - Thermal envelope is anywhere in the property where the main insulation is, not the boundary between inside the property and outside the property - Heat lost into boxing in doesn't just disappear, it moves to cooler areas of the property - Mass flow rate zoning should be minimized - Pipe work should be insulated if it will result in higher thermal output for a space - Pipe work should be insulated to prevent noise and ticking - Pipe work should always be insulated when passing through brick walls Would you agree with me that these points some up your video?

I will always insulate the pipes as it shows a beneficial impact on consumption. (exposed pipework inside room)

Very technical. But not insulating any hot water pipes within the thermal envelope used to be the norm anyway years ago. When did they start doing it and why. Would be my question. I don't follow all the technical mumbo jumbo but I just think a hot pipe radiating heat back into the room isn't doing any harm and as you say may be a benefit, so we never insulated them.

Recent building regs say all should be insulated

Heat lost in the floor void is slow to make its way through to the room (carpets flooring etc) the whole point of insulating is so the heat goes where you need it straight away. The quicker the rads heat up, the quicker the stat clicks off surely the stat takes longer to get to temp when the temp at the radiators is lower as heat's been lost under the floor and therefor slow to reach the room. I thought the myth of keeping a constant temp was long proven wrong? Most efficient way is to just heat when needed and fluctuating stat temps lend more to insulating pipework in my opinion

I believe insulation should be insulated when hot water is exiting the boiler. Return flow should not be insulated from the last rad pipe to the boiler, you allow more condensing. Not insulating pipes going to radiators means you are heating voids and walls that lose heat but not directed at where you want heat . The greatest loss of heat should be from the rads. If your return heat remains too high then either your boiler cant condense or the output flow temp is too high or the rads are too small to vent heat. The aim should be to dump as much heat to the biggest heat emitter (rads/underfloor heating to the floor above) and cut the heat returning to the boiler so condensing works under the delta needed and that you are not sending too high a flow rate temp to the rads that cannot be vented in time within the flow rate pressure. It maybe that the flow rate is too high to vent heat in time. Should boiler makers understand that cutting pump flow rate to vent heat might cut the returning flow rate temp. After all the lower the returning flow rate temp, the more it can condense that remaining heat while knowing too cold a return temp will require more kw to boost the output temp. Maybe this is there yet condensing levels are low in reality due to boiler oversizing, poor moderation, overshooting room temp (no opentherm ability), minimal deployment of weather compensation and poor rad performance/size for tge room they are in. Yes heat will vent internally but humans dont react to temp like a thermal store equalising. No more than most car drivers going at moderate speeds to avoid using the brakes even if transit time would be the same in reality.

What about under kitchen units?

Part Lsays insulate all pipe work. Even flow and return and hot no matter where boiler is installed.

I like the notion, it’s pretty funky, but it is obviously bonkers (I love your usual logical stuff, but hands up eh?) Yes, heat within the envelope is always within the envelope but the notion that having uncontrolled heat is a good idea is, to be quite frank, potty. Also, spot heat, where heating pipes run under timbers etc. can cause twisting and buckling of structural and decorative timber work due to the differential drying caused by having a hot spot where uninsulated pipes run their narrow route. Who hasn’t even had to try to relay a cupped floorboard, dried hard on one side and buckled by the heat over an uninsulated pipe run in the landing of a Victorian property? Could you design a property that utilised heat from uninsulated pipework within the envelope, yes undoubtedly so. I’d also venture that we could manage without emitters / radiators by running great lengths of uninsulated pipework to a carefully calculated design . . . but I won’t because that would be silly too. This is not your usual fare, you’re usually talking sense and educating folk but this is a space filler to get a video,out while bereft of useful content. You’re far better than this and you know it. Please give your head a wobble and then return to dazzle and amaze again. Thanks 👍

I have no lagging in pipes and they froze

So to be fair, the real answer to this video is that you should consider every pocket or a wall as an individual "heater". This is not a zero/one scenario, you can insulate half of the pipe in the void, or use very thin/thick insulation on purpose.

Is this not against nee build regulations now? I know the update was vague at best but have seen ‘unheated space’ interpreted as pipework underfloors and such. Not digging you out, genuinely curious as it seems the reg is not black and white

One of my customers likes to lag heating pipes under first floors, it makes running additional pipework challenging due to lack of space, he is not the sharpest knife in the drawer 🙄

So really the title should be 'Stop insulating ALL pipework', which is actually kind of common sense when it's looked at analytically - problem is that plumbers and building regs people try to apply the same brush to every situation and either see it as an all or nothing. At least as a DIYer some logic can be applied, provided the previous numpties have or haven't done it properly on impossible to access spaces!

then you have condensation from heat pump lines.

Okay. Just pulled all me lagging off me pipes and they froze and burst, flooded me house and drowned me cat. You happy now?

Hehe, loving the Thermodynamics

Why would you want to heat ceiling voids etc. Far better to keep all that heat for radiators which are more efficient at warming rooms

I have old boiler (1970) in unfinished basement. After exiting the boiler, the 28.5mm pipe runs 13 m through the basement before splitting to warm the living spaces. I think I will insulate this. There’s maybe 5-6 m exposed on the return but that has some fins and heat removed there helps warm floor with piping and room above that doesn’t have baseboard radiators.

What about the risk of not insulating the heating pipework in areas where the cold water pipework is within the vicinity(cross contamination of heat). I wonder how many combi boilers have the cold water encased within the f&r pipework in the same notch ? Back to the legionella argument again.

9 out of 10 times ignore this and insulate your pipes. This only works if your house is very well insulated and you heat your whole house at all times.

Beware counter-flow heat exchange; that is, where flow and return (or other) pipes are close together, heat transfers from hotter pipe to cooler pipe.. this is very bad news for efficiency of heat production and delivery by condensing boilers.. and bad news for delivery of heat to furthest heat emitters (radiators) in any heating system that uses radiators. For this reason, I'd insulate the (hot) flow pipework nearest the boiler and between pipes in long runs under floors etc.. also insulate DHW (hot tap) flow pipes to see more rapid delivery of hot water to basin/sink. CIBSE is right, of course.

I am suspicious that this removes some authority from the TRV.

It’s a statutory requirement to insulate all pipework inside the envelope. With good buildings we have more issue with overheating.

Are you on the new gym face advert on TV?

Regulation 4.24 from Part L now negates this video.

Finally someone who knows what they are talking about 👏

Can’t trust a man who doesn’t know that wearing a baseball cap inside the house doesn’t contribute to the thermal envelope. Also his head is on back to front.

I disagree and on house I'm paying £18 for month.

a simple comment would have been, hey people you don't need to go into your boiler room and put insulation around your copper pipes.

???

Telling people to not Insulate pipework is so dumb. Allowing pipework to Heat underfloors, for example. Flow and returns from the boiler to the cylinder will just give added unnecessary heat in the summer. Admittedly it’s only for a short period of time but regardless when it’s 40 degs outside you don’t want to keep adding pointless heat. 9mm of lagging will avoid this issue significantly. Your idea only works in the winter. And then it’s sketchy and not advisable as it’s not covering building regulations which specifically states pipework should be lagged to prevent heat loss to conserve energy.

To make heat my heat pump has 2 big fans 2 pumps 1 condenser to bring it up to heat and cost a lot more than my gas fire which heats the room I am in the heat pump runs all through the 4 bedrooms kitchen and bathroom do the sums in cash.10 minute gas, toasty 2 hours heat pump not so toasty and skint.

Another lot of heat geek flawed science - so now plasterboard, floorboards, carpets etc are more efficient heat emitters than radiators......interesting. Also not sure you're right on 2022 regs either.

Your cap is on the wrong way

I think you may be getting so over obsessed with increasing the COP to maximise efficiency that common sense is going out of the window. We are moving away from gas/oil heating and smart heating controls with motorised TRVs which gives us the ultimate in control with fast warm up temperatures and zoning to avoid wasting heat in unused rooms, to heat-pump technology which by it's very nature has to be on all the time, heating rooms and areas that don't need to be heated just so they can work efficiently. It seems a bit of a backward step to lose the convenience and comfort of fast warm up times and zoning by room due to the inherent limitation of heat-pump technology, which requires heat to be dumped anywhere within the thermal envelope in a desperate measure to keep the COP high in line with a manufacturers spec and/or your own target value, irrespective of whether the heat is actually desired in that specific area. I just don't see how heating rooms that don't need to be heated can be efficient in terms of overall energy usage, even if the system COP means it's running efficiently on paper.

Poor advice on the basis that you've oversimplified the problem. Insulation ensures heat is delivered to where its required at the correct temperature. Taking all the lagging off your pipes you could be dumping heat in parts of the house where you don't want it. Then leave other parts of the house where you do need the heat lacking sufficient flow temperature for the heat emitter to work as designed. I've come across this in the field, was a child's bedroom right above the boiler the main distribution pipework running right under the floor boards, the result was a kids room that's far too hot whenever the heating is run. Solution to reduce the boiler flow temperature, which resulted in the extremities not getting sufficiently warm. Optimal solution lag the pipe work which should have been done upon installation of the central heating system.

Sorry but this fellow is 100% wrong. Heating systems are designed such that they require liquid at a certain temperature delivered to them. The system then distributes the heat in the right amount to the right places. If heating pipes aren't insulated, the heat distribution units can't deliver enough heat to the right places. Heat lost from uninsulated hot pipes rises up thru walls and chases and is lost to the outdoors. Or if uninsulated pipes run near exterior walls or roof, they lose heat thru the walls or roof. And uninsulated pipes overheat some areas while leaving other areas without enough heat. I've been designing thermal insulation systems since 1972 and have heard many mis-informed people say the same thing as this fellow. It would be a mistake that''s hard to fix if you follow such advice. Insulation is required by building codes for hot pipes (heating pipes and domestic hot water pipes) on every commercial and institutional project in the developed world - because it reduces energy costs and makes the heating system work as it was designed to work.

please read part L

Says a man who doesn't know what way round to wear a hat!

Ahh,common sense and logic prevails atlast.

I don't think this is good advice because I'd much rather have a simple rule to insulate it all to make sure secondary returns get insulated. Oh wait noone in the UK knows what a secondary return is.

Ooof. You just lost all credibility. Condensation from cold pipes will drip, cause water damage and mold. Regardless of what season you’re in one of your mini split lines is going to be below the dew point. Better to fully insulate all piping. Armature hour here.

Anyone with a cat knows if there is uninsulated pipework a cat will find it and lay down on the floor causing a serious trip hazard which may result in persons falling down the stairs to their death. Only a cheapskate feckwit doesn’t insulate pipework.

Boy are those hysterical hand movements of yours irritating !!!!!!!!!!!!!