How Cold Winters Change Underfloor Heating Design in Central Asia

Central Asian winter design conditions can vary by more than 10 K within one country. Because a floor's surface-temperature ceiling caps the heat one square metre can emit, colder sites need tighter pipe spacing, stronger insulation, higher flow temperatures or a mixed-emitter scheme — and each choice rewrites the purchase list.

Publicly filed project documents give −28.9 °C for Astana, −20 °C for Almaty with a 179-day heating period, and −31.2 °C with a 209-day heating period for a northern regional project. Importers should therefore freeze the climate inputs first, then let EN 1264-3 and the local code drive the specification.

Key facts

• Astana: climatic zone IВ, coldest five-day outdoor design temperature −28.9 °C (СП РК 2.04-01-2017, Building Climatology).
• Almaty: −20 °C, 179-day heating period (СНиП РК 2.04-01-2017, as applied in a filed project design).
• Northern Kazakhstan residential project (2025 environmental filing): −31.2 °C at 0.92 reliability, 209-day heating period, mean heating-season temperature −6.3 °C.
• Against a 20 °C indoor setpoint, Almaty and Astana imply design temperature differences of about 40 K and 48.9 K — roughly a fifth more heat load for the same building envelope (arithmetic derived from the values above, not a code conclusion).
• EN 1264:2021: Part 2 determines thermal output by calculation and testing, Part 3 covers systems, components and dimensioning, Part 4 installation, Part 5 wall/ceiling heating and floor cooling; it applies to water-based systems embedded in the building fabric, not electric systems.

Climate inputs must become procurement inputs

Design conditions can differ substantially within one country. The values in public project files are project-specific examples, not universal values for every city. Before comparing supplier quotations, the buyer should request:

• design outdoor temperature and the governing local code;
• heating-season length;
• indoor design temperature and permitted floor-surface temperature;
• the project's heat-load calculation;
• supply and return-water design temperatures;
• system pressure, water-quality and oxygen-barrier requirements.

Without these inputs, two quotations may look comparable while supporting different design assumptions.

Why the same pipe spacing does not fit every project

Water-based embedded surface heating must be designed within the limits of the floor surface and the building envelope. The EN 1264 series separates heat-output calculation, system sizing and installation requirements. Where the heat load is higher than the floor can safely deliver, the design may need a smaller pipe spacing, improved insulation and floor construction, a different water-temperature strategy within applicable limits, or a hybrid system using radiators or fan-coil units.

This changes the bill of materials. A floor-only system may require pipe, manifold and controls. A hybrid system may also require radiators, valves, mixing equipment and additional heat-exchange capacity. A pipe-only quotation is therefore not a complete system comparison.

Three decisions that severe climates amplify

1. Heat-source connection. A district-heating connection and an independent boiler system create different secondary-side temperatures, pressures, water-quality conditions and control requirements. The design must establish whether direct connection is permitted or whether a heat exchanger and mixing arrangement are required.

2. Pressure, water quality and oxygen barrier. High-rise and district-heating projects need a clear definition of static pressure and pressure fluctuation. Oxygen diffusion can also affect steel components and valves. The required pipe construction — such as an aluminium-composite or EVOH oxygen-barrier structure — must be selected against the project specification and the manufacturer's written technical documentation. SANLI PIPE's published product information covers aluminium-composite pipe, PE-RT underfloor-heating pipe and aluminium-alloy oxygen-barrier PE-RT pipe; the applicable construction, long-term temperature performance and oxygen-permeation data should be confirmed for the specific model and project before they enter a contract.

3. Thermal inertia and zoning. Wet screed systems heat up and cool down slowly. In long heating seasons of around 200 days, room-by-room control, actuator quantity, manifold circuits and sensor arrangements should be fixed before procurement. A package described as "complete" still requires confirmation of communication protocol, electrical specification, plug standard and destination-market requirements.

Freeze risk belongs in the technical agreement

Power interruption, gas interruption, valve failure or an unoccupied building can expose water-filled circuits to freezing risk. The design response may include avoiding unheated zones, providing drainage slopes and vent/drain points, and defining whether antifreeze is permitted and at what concentration. Antifreeze compatibility with the pipe, adhesive layers and seals must be confirmed in writing by the relevant manufacturer; it should not be inferred from general industry practice.

Turn every design input into an acceptance clause

A quotation without corresponding technical and acceptance clauses is primarily a price comparison, not a system comparison.

Practical conclusion for importers and system buyers

For Central Asian projects, the right procurement sequence is: define climate inputs, calculate the heat load, determine the system architecture, freeze the technical agreement, then compare pipe and component quotations. This sequence helps importers, distributors, brand owners and system manufacturers reduce late changes caused by incompatible specifications.

Zhejiang Sanli Pipe Technology Co., Ltd. has operated since 2002 and runs 20 pipe production lines. Its range covers aluminium composite pipe, PE-RT underfloor-heating pipe and aluminium-alloy oxygen-barrier PE-RT pipe. The full product line holds EAC certification; project-specific insulation, OEM / private-label manufacturing (MOQ from about 10,000 metres) and video factory audits are available. Construction, performance and destination-market conformity must be confirmed in writing for each project. See the underfloor-heating pipe overview, sizing and standards and the one-stop supply platform.

Frequently asked questions

Can one underfloor-heating specification cover the whole of Central Asia? No. Design outdoor temperatures filed for Kazakh projects range from −20 °C (Almaty) to −31.2 °C (northern regional project), and heating periods from 179 to 209 days. With the same pipe pitch and floor construction, those sites deliver different heat output per square metre, so a single "universal" specification satisfies neither. Specify per project and per oblast.

Which three numbers must a buyer obtain before asking for a quotation? The design outdoor temperature, the heating-period length in days, and the room design temperature together with the permitted floor-surface temperature. Without them, two quotations cannot be compared, because the pipe spacing, loop count and emitter mix that follow from them are unknown.

Can underfloor heating alone meet the design heat load in a severe climate? Only if the calculated load per square metre stays below the floor's permitted output. When it does not, the design options are tighter pipe spacing, a higher flow temperature, better insulation and floor construction, or combining the floor with radiators or fan coils. The decision must come from a project calculation under EN 1264-3 and local rules, not from a rule-of-thumb pitch.

What is the most commonly missed procurement item in cold markets? Freeze and interruption protection. Routing of loops through unheated zones, drain-down provisions, and whether an antifreeze solution is permitted at a stated concentration are usually settled by the manufacturer in writing. If the technical agreement is silent on it, the risk sits with the buyer.

Bottom line: in Central Asia's cold markets, comparable underfloor-heating offers come from a shared set of climate inputs and acceptance clauses — not from a shared rule-of-thumb pipe pitch.

Scope and references

This article is a procurement and design-management framework, not a project design, certification opinion or legal opinion. Climate values and heating-season figures are examples from public project documents; the current local code, project design and competent authority remain the controlling references.

Sources: Astana public building project file; Almaty therapeutic complex design file; northern Kazakhstan residential project environmental filing; BS EN 1264 series index.