Should You Insulate Pipework or Not?

Do you have a modern condensing boiler or heat pump?

If so, you may be wondering whether or not to have your indoor heating pipework insulated.

In this guide, we’ll answer this very question and explore what it means to insulate pipework.

We’ll also explore a range of additional frequently asked questions related to the topic.

Let’s dive in!

Should You Insulate Pipework in Your Home? 

The Thermal Envelope

First and foremost, it’s important to define the concept of a thermal envelope in explaining whether or not insulating certain heating pipework would be beneficial or not.

However, this is not the same as the boundary between the interior and exterior of a household. 

What’s more, the thermal envelope may not cover all pipework inside the property since it's entirely possible for pipework to exist inside a household and not be insulated.

Ideally, a thermal envelope should act as a way of keeping heat within your property.

Pros and Cons of Leaving Pipework Uninsulated

Whether or not you should have this pipework insulated would depend on a variety of factors.

However, the general argument for not insulating pipework (where possible) is that insulating pipework within the thermal envelope that is specific to heating may not reduce your energy usage at all.

Moreover, uninsulated pipework can provide additional heat for certain rooms in your property where insulation would act as a prevention.

Other reasons why you might want to avoid insulating internal heating pipework include the cost and time involved in achieving this in the first place.

With that said, you should always ensure that your walls are insulated and sleeved. This can ensure that your household has adequate insulation in itself.

Beyond that, insulating pipework is also not ideal from an environmental point of view due to the carbon impact of producing the insulation material.

However, let’s return to the main point relating to the capacity of uninsulated pipework to heat your property.

With this pipework adding heat to rooms, it could limit the need for your heating system to work as hard as it would otherwise be required.

Another way of looking at this is that uninsulated pipework would maximise the surface area of your heating system.

You may even find that your heating system can be run at a lower flow temperature too.

Either way, uninsulated pipework may improve the energy efficiency of your condensing boiler or the seasonal coefficient of performance or SCOP for those with a heat pump.

So, while it’s true that not insulating your pipework will cause heat to be lost from the hot water travelling via the pipework, since hot air rises, it should primarily heat rooms, thus for the most part, the heat would not truly be lost.

In addition to the point raised above, the thermal envelope will also play a role here in preventing heat ‘lost’ via uninsulated pipework would be largely kept within the thermal envelope due to the insulation featured here. 

In other words, like a closed oven door, the thermal envelope would allow most of the heat escaping the pipework to stay within the various rooms of your property. 

A small amount of heat will make its way through the thermal envelope, however, so you can see how (unless you are able to sufficiently benefit from uninsulated pipework) there remains a small risk that leaving pipework uninsulated could lead to a drop in efficiency.

Obviously, if you are able to lower your flow temperature with uninsulated pipework (in a way that would not be possible if were insulated), you may be able to cancel out or override this downside.

On a similar note, heat zoning areas of your property can have similar disadvantages to insulating pipework.

Ultimately, zonal heating may lead to a loss of efficiency and any benefits its offers could be cancelled out. This would be especially true on very cold days or evenings.

Should You Insulate the Internal Heating Pipework?

Insulating your pipework is likely to offer minimal benefits, if not prove outright more inefficient than simply leaving the pipework uninsulated.

Then when you consider that leaving pipework uninsulated can also make an installation less expensive, faster and more eco-friendly the case for leaving pipework uninsulated is a pretty strong one.

With that being said, the case for insulating pipework may be stronger in certain properties.

For instance, according to CIBSE heating pipework should be insulated unless leaving it uninsulated could help a room or space meet its useful heating requirement.

So, if you have reasons to suspect that (perhaps based on the design of your property or the limitations of the thermal envelope in your household), insulating pipework could make a meaningful difference then you may want to consider going this route after all.

Naturally, if you have opted for zonal heating then keeping the pipework insulated in heat zones that you wish to keep at a cooler temperature than the rest of the property would obviously make a lot of sense.

Otherwise, the heat emitted from the pipework may negatively impact your ability to keep that zone relatively cool, if not make it outright impossible.

Here are some other examples where insulating pipework would likely make sense:

• To Avoid Thermal Output Being Too High for a Space - In general, you want to avoid overheating any space, whether or not it’s one you want to keep particularly cool or simply to avoid going beyond a comfortable or reasonable temperature. Uninsulated pipework running under a well-insulated hallway could make heat control particularly difficult, just to give an example. Too high a thermal output, however, is more likely to prove an issue in commercial buildings which would generally be subject to zonal heating, unlike most domestic properties.

• Lowering Noise Output - If you find yourself being particularly bothered by sounds coming from heating pipework, you may want to consider insulating pipework.

If you have any doubts, it’s best to consult with a professional. That way when having a new heating system installed (e.g., a heat pump), you’ll have a clearer idea as to whether or not you’d like the pipework to be insulated in general or largely left uninsulated. 

Of course, not all installers will allow this decision to be at your discretion and it’s important to remember that not all heating pipework is suitable for being left uninsulated. 

Ultimately, whether or not you should insulate pipework would depend on a range of factors including the type of property you have, whether you are interested in the zonal property and if the installation company would allow you to have a say in this matter.

So, while insulating pipework is arguably not worth it in most cases, particularly for new-build properties, it is likely to remain a common fixture for some time to come.

This may be more out of habit and tradition than anything else at this stage, however, the case for leaving much of the internal heating pipework uninsulated is solid.

For more information on insulation and heat loss, check out our guide to calculating heat loss in a property which delves into the relevant math.