Underfloor Heating: A Complete Guide for Your Home.

Underfloor heating is, in my opinion, the best way to heat a home. It rises from the floor, keeping your feet warm, keeping your body warm — and it uses significantly less energy than radiators. In my own 400 m² house, I turn it on every other day, and we live in short sleeves through the winter. I have installed underfloor heating in dozens of homes between Cascais and Lisbon, and it is consistently the upgrade clients appreciate the most. But the truth is, there is a lot of misinformation regarding costs and installation. In this guide, I explain everything based on my real-world experience of over 25 years in renovations.

The Big Decision: Hydronic or Electric?

The first thing to decide is whether you will install a hydronic (water-based) or electric system. They are not interchangeable — each has its right context and its wrong context.

Maja's rule:

“If it is a new build from the ground up, the preferable solution is hydronic underfloor heating. For apartment renovations, it is better to opt for electric. For those who do not wish to replace their floors, you can even opt for radiant skirting boards. Did you know about those?”

New build? Always install hydronic underfloor heating. It allows for installation with any type of flooring (even wood and microcement), since it operates at low temperatures and the pipes do not come into direct contact with the surface. Here, we can choose whether to heat with electricity (photovoltaic panels), a heat pump, a gas boiler, or a diesel boiler. The installation cost is considerably higher than electric underfloor heating, but compared to radiators, it ends up being about the same — or even cheaper.

Apartment renovation? In most cases, electric is the right choice. It is simpler to install since it doesn't need to be embedded in a new concrete slab (though that is an option); it can sit on top of the slab or even directly over the old tiling.

Full villa renovation? If you are tearing up the entire floor and redoing the infrastructure, and you have access to piped gas, a heat pump, or solar panels — then hydronic remains the best option.

Hydronic Underfloor Heating: What You Need to Know

The hydronic system circulates hot water through pipes installed beneath the floor. It is a closed circuit — just like central heating, but instead of radiators, the heat comes from the entire floor. The difference in comfort is immense: no dust-attracting radiators, no noise, no occupied walls, and no cold spots in the corners.

Heating sources

There are three ways to heat the system's water:

• Gas or diesel boiler — requires piped gas or a diesel tank. The gas boiler is the most common option in apartments.
• Heat pump — more efficient, ideal for villas.
• Photovoltaic panels — combining these with a heat pump is the most economical solution in the long run.

Real running costs

Maja's experience:

“I have a 400 m² house with gas-powered hydronic heating. When I heat it every day, I can see a gas bill of 400/500 a month. That is not much when you consider the volume of the house. A three-bedroom apartment might be 200 euros in gas. It is always much less than what you would pay with electric heating.”

Traditional system vs. next-generation

The traditional system requires 6 to 7 centimeters of thickness (pipes + screed). In a new build, it is always the right choice — it costs three times less than the slim system and works exactly the same.

The next-generation (slim) system is only 2 to 2.5 centimeters thick. It is much more suitable for renovations, but considerably more expensive. The advantage is that the ceiling height isn't drastically reduced and the additional weight on the slab is minimized.

With the traditional system, be prepared: the ceiling height visibly drops, you have to level the entire house to avoid uneven steps between rooms, and the doors must be replaced because you simply cannot have doors that are 10 cm lower, nor can you trim that much off an existing door.

Why a Fixed Price is Impossible

Maja's opinion:

“It is very difficult to talk about installation costs without knowing where we are installing, because it can vary significantly.”

The real cost of installation does not match the generic figures you find online. The piping has to be run to the heating system — boiler, heat pump, or otherwise. And the fixed costs for those components are practically the same whether the house is 50 m² or 200 m². Many offers on the market don't even include the work of the mason, the plasterer, etc., but speak exclusively of the installation itself. That assumes the team arrives when the floor is already broken up and prepared to receive piping, all the chases for the pipes are open, etc. After the installation, the finishing work is once again the client's responsibility.

In a ground-up build, hydronic underfloor heating does not cost much more than traditional heating with radiators. By the time you calculate the price of stylish, beautiful radiators, the final figure ends up being similar — with the advantage that underfloor heating is superior in every aspect.

Electric Underfloor Heating: The Truth About Costs

The electric radiant system comes in several forms: loose cables that must be covered in screed (for all floor types), mesh mats for ceramic tiles, foil mats for laminate flooring, and film for laminates. The most commonly used are heating mats installed directly beneath the flooring. Unlike hydronic systems, these can be placed on top of existing tiles — no new slab, no breaking down walls. The total thickness is just 8 millimeters (5 mm of insulating base + the heating element).

Prices of €30–€50/m² are an illusion

Maja's opinion:

“€30 to €50 per square meter? That is ridiculous. It's a way to sell the project, but if you calculate that you'll pay that, it's an illusion.”

Many websites quote costs of €30–€50/m² for electric underfloor heating per room. In reality, this value varies greatly and also depends on the room's area.

Real example: A 3 m² bathroom. The material (heating mat) costs around €120. But each room requires its own thermostat — and a smart thermostat costs at least €150. We are already at 90€ [per m²] and we haven't even factored in the cost of the mason, plasterer, painter, or electrician.

Electrical capacity: the problem nobody mentions

Before installing electric underfloor heating, it is imperative to verify the maximum allowed electrical capacity of the house.

For a small bathroom, the existing electrical supply might be sufficient. But for larger rooms, it is mandatory to run direct lines from the electrical board — never share circuits with other appliances. Otherwise, when you turn on the underfloor heating and the oven at the same time, the breaker will trip.

Many installers in the Lisbon and Cascais area ignore this issue — “once it's installed, the clients are the ones living there, and if the board trips, it trips.” At Maya’s Homes, we always conduct a preliminary study of the electrical installation before proposing any solution.

Compatible Flooring: Be Careful What You Choose

This is where many people make mistakes — and the difference between the hydronic and electric systems is fundamental.

With hydronic underfloor heating

Because the system has a layer of screed over the pipes, you can lay virtually any finish: ceramic, natural stone, wood, vinyl. There are no significant restrictions.

With electric underfloor heating — extreme caution

Maja's rule:

“Wood is a very poor conductor of heat — think of a wooden spoon. The heat doesn't pass through. Putting solid wood over electric underfloor heating? You will waste a lot of electricity and the result will be mediocre.”

• Ceramic and porcelain — perfect, the best conductor. Warm floors in the winter, cool in the summer.
• Solid wood — I do not recommend it. Poor conductor, high electricity consumption, mediocre result.
• Vinyl — absolutely not. It is a catastrophe over electric underfloor heating. I only advise it if you are embedding cables directly in the screed.
• Laminate — possible, but only with specific brands designed for electric underfloor heating. Most mass-market laminates cannot handle the electric system.

Pay attention to packaging: many flooring materials have an "underfloor heating" icon on the box, but this refers exclusively to hydronic systems. You must verify if it specifies "electric underfloor heating" — they are completely different things.

Brands We Use

At Maya’s Homes we work with Warmup and Rointë — two brands with many years in the market, in-house developed products, and above all, reliable after-sales service. I always prefer to work with those who developed the product and have proven experience, rather than generic brands with zero technical support.

Pros and Cons

Why I prefer underfloor heating over radiators

• Uniform heat — no cold spots in corners, unlike radiators
• All walls remain free — no radiators taking up space and limiting furniture placement
• Silent and invisible — no noise, no accumulated dust
• Heat retention — once the floor is warmed, it maintains the temperature even with the system turned off
• Zero maintenance — unlike radiators that need bleeding, cleaning, etc.
• Compatible with renewable energy (heat pumps for hydronic, photovoltaic panels)

Drawbacks to consider

• Higher initial cost (especially hydronic in renovations)
• Slower response time than an electric radiator (the floor heats up gradually)
• Incompatible with thick rugs — covering the floor drastically reduces efficiency
• Hydronic system: more invasive installation, requires significant structural work
• Electric system: power limitations in older apartments can disrupt usage (tripping the breaker)

Maintenance and Proper Use

Electric system

The great advantage: zero maintenance. But there are fundamental rules for usage:

• Heat the space gradually — from 19° on the first day up to 25° max (on the second day) to prevent damaging the floor. With the thermostat at 21°, you will have a pleasant environment that feels like 24°.
• Never install under vinyl flooring — absolutely unadvised.
• Avoid rugs on top of the underfloor heating — the more you cover, the harder the system works and the more electricity it consumes.

Hydronic system

• Minimal maintenance — much less than traditional radiators
• Check the system pressure annually (1.5–2 bar)
• Check the antifreeze fluid every 3 years
• Do not place thick rugs or furniture without legs over large areas of the floor

The Most Common Mistakes I See Every Day

Maja's analogy:

“I don't dye my hair at home. I tried it, it came out green once, orange another time, and now I go to the hairdresser and know I will leave looking beautiful. The same applies to underfloor heating installation — it is very easy to buy a roll of electric underfloor heating, but the installation is where the problems begin.”

• Choosing the wrong flooring — putting vinyl over electric underfloor heating is a catastrophe. Many people do it without knowing.
• Failing to check the electrical capacity — installing without knowing if the house can handle the load. The breaker trips constantly.
• Installing where you shouldn't — under the bathtub, under the shower tray, under the cabinets.
• Faulty installation — the system can overheat.
• Installation of the thermostat, electrical lines, etc. — in theory, it is all simple.
• Rushed installations — pulling wires from a random socket through technical trunking. Maya’s Homes does not do half-measures. Things are either done right, or it is better we don't do them at all.

For every installation, it is imperative to conduct a preliminary study and be brutally honest with the client. I see the problem every day — not just with underfloor heating. For many, the priority is just to sell. I do not see things that way.

Frequently Asked Questions about Underfloor Heating

How much does it cost to install underfloor heating in Portugal?

It depends heavily on the system and the context. The hydronic system costs 2 to 3 times more than the electric to install, but it is much more economical to run. Be skeptical of anyone presenting figures of €30–€50/m² without specifying exactly what that covers.

What type of flooring is compatible with underfloor heating?

With the hydronic system, practically any flooring works. With the electric system, ceramic is the best option. Avoid vinyl and solid wood. Laminate is only compatible with specific brands designed for electric underfloor heating — note that the icons on the packaging often refer only to hydronic systems.

Is underfloor heating suitable for Portugal?

Absolutely. Although the Portuguese climate is mild, old stone houses and apartments — especially in the Cascais and Lisbon area — can be very cold in the winter due to humidity. Underfloor heating offers superior comfort — in my own 400 m² home, I turn it on every other day, and we live in short sleeves.

Can underfloor heating be installed during renovations?

Yes. The electric system is ideal for renovations — it can be installed on top of existing tiles with only 4 to 8 mm of thickness. The hydronic system in renovations requires much deeper structural work and is only viable when you are removing the entire floor.

Can I install underfloor heating myself?

Electric? You could. But as the saying goes, cheap ends up being very expensive. I do not recommend it. It is also important to verify that the company in question has experience with this type of installation. Talking is easier than doing. Hydronic flooring must imperatively be installed by certified companies.