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Underfloor heating offers several benefits such as maximizing the available floor space and providing uniform heat to a room. Moreover, it’s a safer option for children’s bedrooms than conventional heating systems like radiators. Not to forget that it increases the overall efficiency of your home’s heating system and reduces impact noise & transmission of airborne contaminants.
These benefits have made underfloor heating an excellent option for heating various areas in your home. In most cases, it’s only used on ground floors as it’s relatively quick and straightforward to install. However, many homeowners are now considering installing underfloor heating upstairs to keep the bathroom and bedroom floors warm and toasty on a cold morning.
But, can you have underfloor heating upstairs? In this post, I’ll take you through the practicalities, problems and benefits of installing underfloor heating upstairs to help you make an informed decision!
First, let me answer your question!
Is it possible to have underfloor heating upstairs?
Yes, you can have an underfloor heating system on both the ground floor and the first floor of your home. So, if you’re undertaking a new build or renovation project, you can consider upgrading to the luxury of UFH heating for the upstairs.
However, there are various factors you should consider, such as the type of floor structure in your home’s upstairs level. Interestingly, a UFH system can be directly installed over solid subfloors such as existing plywood, tiles, wooden floors, and concrete floors.
Secondly, installing underfloor heating upstairs can be a capital-intensive project. Therefore, extensive installation can be challenging. In addition, you need adequate space between the floor surfaces to accommodate the in-floor heating system
Other than that, installing an underfloor heating system on both the ground and first floor is a relatively simple task. Moreover, most homes combine radiators on upper floors with downstairs underfloor heating for improved efficiency.
On top of that, underfloor heating for upper floors should be lightweight and safe to install. At the same time, it should offer little or no height build-up and allow for flexible installation.
Hydronic Vs Electric UFH; Which is better for Upstairs Underfloor Heating?
Both electric and hydronic systems are suitable for upstairs underfloor heating. However, the best option for your home will depend on various factors like ease of installation, initial cost, and change in floor height.
- Ease of installation
Wet/ hydronic UFH systems are mainly used in new buildings. This is because they’re easier to incorporate into new builds, as opposed to reconstructing the entire floor to fit them in. In comparison, electric underfloor heating systems are commonly used in existing homes as they’re relatively easy to retrofit into the property.
- Initial cost
Although hydronic UFH systems operate with low running costs, they have a higher initial installation cost than their electric counterparts. For instance, the best electric underfloor heating mats cost around $50 to $75 per sq m. However, this cost may vary depending on the insulation for underfloor heating, technician’s fees, and heater controls. Nonetheless, hydronic heating systems are more costly to install than electric systems as they might cost you thousands of dollars.
- Changes in Floor Height
Lastly, wet underfloor heating systems require a lot of space for installation and raise the floor height more than electric UFH systems. On the other hand, you can easily fit electric underfloor heating into the upper floors with little to no changes in the floor-to-ceiling height.
Benefits of installing underfloor heating upstairs
- Improved heating efficiency
One major benefit of using UFH with screed or concrete in a suspended or ground floor surface is that it improves the efficiency of the heating system. That’s because, unlike radiators, an underfloor heating system generates the same heat temperatures for both floors.
However, to ensure that underfloor heating is ideal for your project, you should ensure that the building’s airtightness and insulation have been addressed.
In essence, the water temperature with a conventional radiator heating system is about 65 – 75 deg C, while the pipes in a typical screed or concrete floor are around 35 to 45 deg C. This reduction in the water temperature produced by the heating systems means that an underfloor heating system requires less energy to heat a building.
Unfortunately, upper floors are usually made of suspended timber, while concrete is used on ground floors. Therefore, upper floors require a suspended UFH system, which may involve installing pipes under a traditional timer deck such as chipboard, plywood boards, or tongue & groove.
Since timber boards act as an insulation layer, they need a higher temperature, thus reducing their efficiency. So, to get the same efficiency as the concrete ground floors, you might have to use concrete on the upper floors.
Heat pumps for underfloor heating
Alternatively, you can consider using a heat pump system for your underfloor heating as recommended by the RHI (Renewable Heat Incentive), Part L building regulations, and the government’s aim to see all buildings meet NZE standards in the coming years. Heat pumps efficiently produce heat at lower temperatures, making them a great option for upstairs underfloor heating.
- Maximizes available floor space
Installing underfloor heating on your upper floors saves the space occupied by radiators and their impact on room layouts. Besides, installing radiators near windows allows a lot of generated heat to escape. On the other hand, installing a radiator on other walls comprises the choice of furniture layout in the room.
Therefore, radiators can reduce the usable space within a room by around 10 – 15%. In comparison, underfloor heating maximizes the available floor space and increases the usable floor area in each room. Also, this makes upstairs underfloor heating an excellent option for other buildings like apartments, motels, hotels, student accommodations, etc.
- Increased thermal mass
Most modern buildings are constructed with lightweight materials like timber frames, lightweight blocks, SIPs, or light gauge steel frames. Also, they can be constructed with techniques that effectively separate the thermal mass from the building’s interior. For instance, mounting plasterboard linings on battens introduce an insulation layer of still air or polystyrene.
These layers of underfloor heating act as a thermal mass for the building and allow the heating system to absorb, release, and store heat. Moreover, it ensures that there are no temperature fluctuations due to heat loss or gain.
To get the best out of your UFH and thermal mass, you should choose the appropriate floor coverings such as dense timber, carpet, tile, and underlays.
Drawbacks of Installing Underfloor Heating Upstairs
The most common issues associated with installing underfloor heating upstairs are; wiring problems, air-locked pipes, worn-out pumps, and zones not heating up.
- Wiring Problems
Wiring problems in electric UFH systems can prevent the boiler from engaging properly or stop the thermostat from working.
Worn Out Pipes
Water pumps for upstairs underfloor heating tend to wear out over time, especially when used with high capacity and long systems across multiple floors.
Air Locked Pipes
Air can get trapped in the pipe network for underfloor heating, which reduces the effectiveness of the heating system.
Most popular underfloor heating systems for upper floors
Although there are many types of underfloor heating systems for upper floors, they can be classified into 2 main categories;
- Metal heat transfer plates
Metal heat transfer plates are either installed between or on joints to hold UFH tubes. The plate is specifically designed to serve as a thermal conductor, thus improving the ease of installation and response times.
Different types of metal heat transfer plates can be grouped into various categories, depending on their quality and where they are installed. In general, they can either be installed on or between joists of suspended floors upstairs. Therefore, you should choose a UFH system that can either be fitted between timber joists from below after you lay the deck or on first-floor timber joists from above before you lay the deck. This will allow the UFH installer or contractor to work on-site, without disrupting the build schedule of other operations.
Installing underfloor heating between joists
Installing upstairs underfloor heating between timber joists from below after laying the upper-floor deck is safer and quicker. Better yet, it allows other tasks to continue upstairs during UFH installation.
Installing underfloor heating on joists
Alternatively, you can fit the heat transfer plates on timber joists and install the heating tuber from below if it’s convenient.
- Low-profile pre-routed gypsum boards
Although low-profile pre-routed gypsum boards are a retrofitted underfloor heating system, they’re regularly used in new builds. More notably, they’re commonly used when it’s impractical to install UFH between joints because of the floor joist structure. However, you can also use them if you have decided to install underfloor heating later in the build schedule.
One benefit of using low-profile pre-routed gypsum boards is that they provide good acoustic performance. Thus helping to reduce impact and airborne noise transmissions to the rooms below. In addition, these systems are easy to install since they’re laid over the floor deck. Not to forget that they provide quick response times and uniform heat output since the material conducts heat well.
Best of all, you can fit floor finishes over these panels since the overall height build-up is only 15 mm. This makes it a popular retrofit UFH solution as it will fit perfectly on top of your existing floor.
Factors to consider when planning to install underfloor heating upstairs
Overall, it’s possible to install underfloor heating upstairs. However, there are some considerations you need to bear in mind during the installation and design stages. Some of these factors are;
- Manifold location
Before you choose where to install the manifold, carefully analyze the design of your upstairs underfloor heating system. Generally, you should choose a location that allows you to install the manifold with ease. Some of the best places to put a manifold are; under the stairs, in the storage area, or on the wall.
- Type of heat source
The ideal type of heat source for upstairs underfloor heating systems depends on the size of your floor space. For instance, a regular boiler is suitable for smaller systems since it provides sufficient pump capacity. However, if you’re using a GSHP (Ground-Source Heat Pump), it should have sufficient heating loops and be of adequate size to power the UFH system.
A border zone in an underfloor heating system may be ideal if the building has a glass facade. This will help the system generate enough warmth and prevent cold traps to increase comfort.
- Heat loss calculation
Most homeowners usually overlook the issue of heat loss calculation when installing underfloor heating upstairs due to the involved financial implications. However, it’s good to invest in these calculations and incorporate them into your UFH system design as they show the ideal temperature required for different areas.
Although installing underfloor heating isn’t as cheap as alternative options like the use of radiators, it’s a good investment. Besides, it will help you save money on your energy bills in the long run since UFH is an environment-friendly heating solution. Best of all, you can either choose a water-based or electric underfloor heating system for the upper floors. However, electric heating mats are usually recommended since they’re easier to retrofit upstairs.