A well-functioning plumbing system is crucial for any comfortable home. When you have hot water downstairs but not upstairs, it can be a real inconvenience. In this comprehensive guide, we will delve into the most common reasons for this issue, along with effective solutions to get your hot water flowing again.

Common Causes of No Hot Water Upstairs

There are several reasons why you may experience no hot water upstairs. Some of the most common causes include:


Valves are frequently disregarded culprits of no hot water in particular areas of a house. It is customary for plumbers to implement valves, such as ball valves, in water lines that lead to bathrooms. This permits them to cease the water supply to certain rooms, making it easier to perform repairs without the need to turn off the water supply to the entire home.

Inadvertently, these valves may be accidentally bumped, causing the availability of hot water to be reduced or turned off. To identify if this is the root cause, adhere to the following steps:

  1. Locate the valve for the affected tap. Typically, these valves can be found beneath a sink, like a bathroom sink. In case it cannot be located, trace the pipe from the water heater to the bathroom, and the valve should be easily noticeable.
  2. Meanwhile, look for a temperature-regulating valve, which may be installed in certain households, but is not a regular practice. When you possess a temperature-regulating valve, it could be the guilty party.
  3. Verify the valve is completely open, then test your water. If it is a conventional shut-off valve, turn it until it is completely open, and test your water. Should you encounter difficulty while turning the valve, it is likely that it requires replacement. Although you may be capable of replacing the valve yourself, it is advisable to consult a plumber to ascertain that this is indeed the issue prior to proceeding.

By examining the valves in your home, you might be able to promptly identify and rectify the problem of the lack of hot water upstairs.

Gravity-fed hot water systems

Gravity-fed hot water systems, often found in older homes, rely on the force of gravity to distribute hot water from the storage tank to various fixtures throughout the house. These systems consist of a cold water storage tank, usually located in the loft or attic, and a hot water cylinder, typically found in an airing cupboard. The water pressure in a gravity-fed system is determined by the height difference between the storage tank and the taps, known as the “head.”

In a gravity-fed system, when the hot water tap is opened, cold water from the storage tank flows into the hot water cylinder, pushing the hot water out of the cylinder and through the pipes to the tap. Due to the reliance on gravity, the water pressure in these systems can be significantly lower compared to modern, pressurized systems. Consequently, if the head is insufficient, the hot water may struggle to reach upstairs fixtures, resulting in no hot water or reduced water flow in those areas.

Distance from your hot water heater

The distance between the water heater and the fixtures in your home can have a significant impact on the availability and temperature of hot water, especially in upstairs rooms. As hot water travels through the pipes from the water heater to the taps, it loses heat along the way due to the process of conduction. The longer the distance, the greater the heat loss, which can result in lukewarm or even cold water reaching the upstairs fixtures.

Furthermore, the increased distance can also lead to a delay in hot water reaching the tap, as it takes more time for the hot water to travel through the pipes. This is particularly noticeable in larger homes with extensive plumbing systems. In some cases, the delay might be mistaken for a lack of hot water when, in fact, the hot water simply takes longer to arrive at the tap.

Blocked pipes

Blocked pipes are a common cause of restricted hot water flow in upstairs fixtures. Several factors can contribute to pipe blockages, including mineral deposits, debris, and corrosion. Over time, minerals like calcium and magnesium can accumulate on the inner walls of the pipes, especially in areas with hard water. These deposits, known as limescale, can gradually build up, narrowing the pipes and obstructing the flow of hot water.

Debris, such as dirt, sand, or even small objects, can also find their way into the pipes and cause blockages. This is more likely to happen when there is a lack of proper filtration or if the plumbing system has been compromised in some way, like during construction or renovation work. Corrosion is another contributing factor, particularly in older homes with metal pipes. As the pipes corrode, rust and other corrosion products can accumulate and restrict water flow.


Airlocks are another common issue that can lead to a lack of hot water in upstairs fixtures. An airlock occurs when air becomes trapped within the plumbing system, creating a blockage that prevents water from flowing freely. This can happen for several reasons, such as improper pipe installation, sudden changes in water pressure, or when the water supply has been turned off and then back on again.

When airlocks form in the hot water pipes, they can impede the flow of hot water to upstairs taps, causing either reduced water pressure or no hot water at all. Identifying an airlock can be challenging, as the symptoms may resemble other plumbing issues. However, if you experience a sudden loss of hot water in one or more upstairs fixtures while the rest of the house has hot water, it may be indicative of an airlock.

Thermostatic mixing valve issues

Thermostatic mixing valves (TMVs) play a crucial role in maintaining a consistent and safe hot water temperature in your home. These valves blend hot water from the water heater with cold water to deliver water at a comfortable temperature through your taps, showers, and other fixtures. TMVs are designed to prevent scalding and thermal shock by keeping the water temperature within a safe range, typically around 50°C (122°F).

Issues with thermostatic mixing valves can lead to a lack of hot water in upstairs fixtures, as well as temperature fluctuations and inconsistent water flow. There are several potential problems that can affect the performance of a TMV, including:

  1. Incorrect temperature settings: If the TMV is set too low, it may not allow enough hot water to mix with the cold water, resulting in lukewarm water or no hot water at all. To fix this, you can try adjusting the temperature settings on the valve according to the manufacturer’s instructions.
  2. Debris or mineral buildup: Over time, debris and mineral deposits can accumulate within the valve, affecting its ability to regulate water temperature. This can be particularly problematic in areas with hard water. To address this issue, you can clean the valve by disassembling it and removing any visible debris or mineral deposits. Be sure to follow the manufacturer’s guidelines for cleaning and maintenance.
  3. Worn or damaged components: The internal components of a TMV, such as the thermostatic element or the valve seat, can wear out or become damaged over time. This can result in the valve failing to maintain the correct water temperature or even leaking. In such cases, you may need to replace the affected components or the entire valve.

How To Fix No Hot Water Upstairs Issues

Fix heat loss due to distance

One solution to minimise heat loss and reduce delays is to insulate the hot water pipes. Proper insulation can help maintain the water temperature as it travels through the pipes, ensuring that the hot water reaches the upstairs fixtures at the desired temperature. Additionally, homeowners can consider installing a hot water recirculation system, which continuously circulates hot water through the pipes, reducing the waiting time for hot water at the tap.

Fix gravity-fed hot water issues

One potential solution is installing a booster pump or upgrading the gravity-fed system to a more modern, pressurised system, such as a combination boiler or an unvented hot water cylinder. Alternatively, a different style of hot water system could be installed outside the home and plumbed in.

Fix blockages in your hot water pipes

Identifying blocked pipes can be challenging, as the issue may manifest in various ways, such as reduced water pressure, uneven water temperature, or noisy pipes. To diagnose the problem, homeowners can visually inspect the exposed pipes for signs of corrosion or damage and monitor the water pressure and temperature at different fixtures throughout the house.

Clearing blocked pipes may require different approaches, depending on the severity and nature of the blockage. For minor blockages, using a plumbing snake or a chemical drain cleaner may be sufficient to dislodge the obstruction. In more severe cases or when dealing with damaged or corroded pipes, it’s best to consult a plumber who specialises in hot water repairs to assess the situation and recommend appropriate solutions, such as pipe replacement or water softening systems to prevent future mineral buildup.

Fixing airlocks

To resolve an airlock, you can try a few DIY methods. One approach is to turn off the main water supply, open all the affected hot water taps, and then turn the water supply back on. This can force the trapped air out of the pipes and restore the flow of hot water. Another method involves using a hose to connect the hot and cold water taps of the affected fixture, turning on both taps, and allowing the pressure from the cold water supply to push the trapped air out of the hot water pipe.

If these methods fail to resolve the issue, or if you’re unsure how to proceed, it’s best to consult a professional plumber. They can accurately diagnose the problem, remove the airlock, and provide recommendations to prevent future occurrences, such as installing air release valves or ensuring proper pipe installation.


In conclusion, no hot water in your shower can be caused by a variety of issues however hot water issues upstairs can be caused by a few key factors, including airlocks, blockages, faulty TMVs, and imbalanced radiator systems. By following the troubleshooting steps and preventive measures outlined in this guide, you can help ensure that your home has a consistent supply of hot water. If you’re unable to resolve the issue on your own, don’t hesitate to call a professional plumber for assistance.