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Author

Przemysław Paziewski

Founder of HeatAlgo, author of the calculation engine to EN 12831 and EN 1264

Przemysław Paziewski

Who writes these guides

Przemysław Paziewski founded HeatAlgo and wrote the engine that does the app's calculations: the room-by-room heat load to EN 12831-1 and underfloor heating to EN 1264.

The technical guides on the HeatAlgo blog are his. Their numbers come from the same engine as the app and sit next to their assumptions: water temperature, pipe spacing, floor covering, room size.

How to check these numbers

One house is calculated in full and published with every input: building elements, rooms, heat load, heat pump, underfloor loops. You can recalculate it yourself.

See the house calculated in full

Guides

Guides he wrote

Milling an existing screed for underfloor heating: when it works and what it costs

Floor milling cuts channels for water underfloor heating into your existing screed. When the floor suits it, what a quote should list, and the alternatives.

Retrofitting water-based underfloor heating: what to measure first

A new screed, a dry system or milling? Measure levels at doors, thresholds and stairs, find out the floor layers and check room heat loss. With a worksheet.

Where should an underfloor heating manifold go?

Choosing an underfloor heating manifold location: one floor, two positions, the pipe runs and loop lengths HeatAlgo calculated, and what to ask your installer.

What should an underfloor heating design include?

Check the drawings, room calculations, loop details and handover scope in a water-based underfloor heating design. Includes a quote-comparison worksheet.

Planning underfloor heating? What to prepare before asking for a quote

Prepare for a water-based underfloor heating quote: floor plans, insulation, floor finishes, heating system and questions for your installer.

Heat recovery in HeatAlgo - air flows and the balance to PN-83/B-03430, step by step

Mechanical ventilation in HeatAlgo: an air flow for every room to PN-83/B-03430, a supply-and-extract balance and unit selection from the EPREL register.

Algo AI - how the assistant reads building documents and what it does with the data

Algo AI reads the design, the window schedule and the certificate, proposes values for the form, answers from the project's data and checks it.

What flow temperature for underfloor heating - and why it decides your pipe spacing

Water temperature and floor covering set a floor's output, not its area. Calculated table: what 30, 35, 40 and 45 °C give per m² under tile, wood and carpet.

Electric underfloor heating loses its subsidy in 2027 - what stays in Czyste Powietrze

From 2027 the programme funds no heating mats, electric boilers, electric radiators or electric underfloor heating. What stays on the list, and what it changes.

Pipe spacing and loop length in underfloor heating - how to work it out properly

The (area ÷ spacing) × 1.1 formula counts neither the run to the manifold nor the setback from the walls. Here is how far off it is, and how to work out a loop from real geometry.

Split heat pump ban 2027: what leaves the market, and what stays

No, an installed heat pump does not have to be replaced. From 1 January 2027 split air-to-water units up to 12 kW on GWP 150 or more leave the market.

The oversized heat pump - why a capacity margin is billed to the client every month

Why a heat pump sized "with a margin" cycles, loses seasonal efficiency and wears its compressor faster - and how to size one from a calculation, not a rule of thumb.

Installer's glossary: heat load, U-value, lambda, thermal bridges

Heat load and equipment sizing terms explained: U-value, lambda, thermal resistance, thermal bridges, n50, bivalent point, SCOP and the heating curve.

A client's glossary: what the terms in your installer's form mean

Your installer is asking for floor plans, sections and a window schedule? Here is what each of those documents is, why it is needed and where to find it.

What a heat load calculation is, and what actually depends on it

The design heat load is the power a house needs in the coldest hour of the year, to EN 12831-1. Worked example: 102 m², 4749 W. What depends on it, what it costs.

How to use the underfloor heating module - a step-by-step guide

Upload and calibrate a floor plan, draw sections yourself or with Algo AI, connect loops to a manifold, and download the report and floor plan as PDFs.

How to send a client the form and get complete data - a guide

From creating the project to accepting the client's data - a simple step-by-step guide, screen by screen, no jargon.