Heat Meter Brands Compared 2026

Heat Meter Brands Comparison Table

The size column shows the models sold on our site; the other columns are based on manufacturer documents. In cells marked Not stated by the manufacturer, this information is not included in the manufacturer documents we reviewed.

* According to the product information on our site (see the Novus Digitermo DTL section).

Another criterion not in the table is the accuracy class. Defined according to EN 1434, this class indicates the permissible error limit; class 2 is more precise than class 3. According to manufacturer and product information, the ultrasonic models on our site are class 2, while the mechanical Minol Zenner C5 ISF is class 3.

Brand by Brand: Strengths and Points to Watch

Minol Zenner: C5 IUF, C5 ISF and IUF

Minol Zenner is the only brand on our site with models from DN20 to DN300: the ultrasonic C5 IUF (DN20–DN40) and the mechanical C5 ISF (DN20) for apartments, and the DN50–DN300 IUF set for building entries and heat substations.

• Strengths: The heat measurement of the C5 IUF is MID approved (Germany, PTB); cooling measurement is additionally certified with Germany's national type approval. The meter can be installed in any position, even upside down. On our site it is offered with a wired M-Bus or wireless wM-Bus option. With the 3 programmable pulse inputs that can be ordered with the M-Bus module, the apartment's water meters can also be read via the same meter. The flow sensor of the IUF set works with two ultrasonic measuring paths and requires no straight pipe before or after it; its lengths are compatible with old mechanical Woltman meters.
• Points to watch: On the C5 IUF and C5 ISF the standard interface is optical only; M-Bus, wM-Bus or LoRa is selected when ordering. The DN25–DN40 lengths of the C5 IUF may differ from other brands (the DN25 model on our site is 260 mm). The DN50–DN300 IUF is a set consisting of a flow sensor, a calculator unit and a sensor pair; its communication and the calculator unit battery should be confirmed when ordering.

Minol Zenner products · Example products: Minol Zenner C5 IUF DN20, C5 ISF DN20, IUF DN50

Calmet PM02

The Calmet PM02 is an ultrasonic heat meter manufactured by FNF Teknoloji in Kayseri, Türkiye. Our site carries the same series from DN15 to DN100; the DN15–DN40 models are threaded, the DN50–DN100 models flanged.

• Strengths: The EU type examination certificate for the DN15–DN40 models is RO-2275-23619, issued in Romania. The meter can be installed on the supply or return line, horizontally or vertically. The calculator unit has IP65 protection, the flow sensor and sensors IP68. Total energy and volume are written to non-volatile memory every day at midnight.
• Points to watch: If cooling is to be measured, the version must be specified when ordering: PM02-H measures heating or cooling, PM02-M measures heating and cooling. DN15 comes in two versions with a nominal flow of 0.6 and 1.5 m³/h. The manufacturer documents do not include a Modbus option; on the DN50–DN100 models, communication is limited to M-Bus and wM-Bus. Only the manufacturer's service center may replace the battery.

Calmet products · Example products: Calmet PM02 DN20, Calmet PM02 DN50

CEM CM-HR

The CEM CM-HR is an ultrasonic heat meter in the DN15–DN40 range; it is produced in heating, cooling and heating + cooling versions.

• Strengths: Wired M-Bus and an optical interface are standard; with wM-Bus/LoRaWAN, NB-IoT and pulse modules it can be adapted to different reading infrastructures. The protection class is IP67. The standard medium temperature is 4–95 °C; an optional 4–130 °C version is also available.
• Points to watch: The flow sensor is installed on the return line. The manufacturer's model numbers do not follow the same order as the sizes; for example, for DN25 there are two models with lengths of 160 mm (CM-HR4) and 260 mm (CM-HR5). When ordering, go by size and body length rather than the model number.

CEM products · Example product: CEM CM-HR DN20

Danfoss SonoSafe 10

The Danfoss model on our site (product code 014U0015) is the SonoSafe 10 and is produced for heat measurement only. The SonoSelect 10 in the same family is a separate model; the manufacturer's cooling approvals belong to that model.

• Strengths: Battery life is 16+1 years from the production date; this is the longest period stated by the manufacturers for the compact heat meters on our site. In addition to the built-in M-Bus and optical interface, there is a free module slot: a wM-Bus (OMS), M-Bus + 2 pulse inputs, 2 pulse inputs or 2 pulse outputs module can be fitted later. It can be installed in any position and requires no straight pipe. The MID certificate is DK-0200-MI004-034 (FORCE Certification, Denmark).
• Points to watch: Since it does not measure cooling, it is not suitable for installations that provide both heating and cooling. The pressure class is PN16, the protection class IP65. The model on our site is for the return line; according to the manufacturer, this setting can be changed on site.

Danfoss products · Product: Danfoss SonoSafe 10 DN20

Honeywell (Resideo) EW700

The EW700 series is an ultrasonic compact meter that measures the energy of heating and cooling water in residential and small commercial buildings; on our site it is available in five sizes from DN15 to DN40. The EW7001AM… designation in the product codes is the order number; the series name is EW700.

• Strengths: The calculator unit keeps heating and cooling energy in separate registers. M-Bus and IrDA (optical) interfaces are standard. The manufacturer states that the meter is fully resistant to external magnetic fields. It can be installed horizontally or vertically. The manufacturer's two documents differ on straight pipe runs: the English data sheet says none is needed, while the Turkish-language installation instructions require at least 10×DN of straight pipe before the meter and at least 5×DN after it; details in our Heat Meter Installation guide. Medium temperature is 4–95 °C, maximum operating pressure 16 bar.
• Points to watch: The data sheet states MID approval and accuracy class 2 but does not give the issuing body or the certificate number; ask for the certificate when ordering. The calculator unit is connected to the flow sensor with a fixed 1 m cable; plan the installation location accordingly. The data sheet does not include a wireless communication option.

Honeywell products · Example product: Honeywell EW700 DN20

İntegral UK-PLUS

The İntegral UK-PLUS is an ultrasonic heat meter manufactured by İntegral Sayaç in Kastamonu, Türkiye; it is available in DN20 on our site. The manufacturer describes this model as a hybrid meter that can work in both heating and cooling.

• Strengths: It is read remotely via a wired M-Bus interface. Medium temperature is 4–95 °C, supply–return temperature difference 3–75 K, protection class IP65; it works with a PT1000 sensor pair with 1.5 m cables. The manufacturer's product page states MID class 2 and CE marking.
• Points to watch: Battery life, MID certificate number and body length have not been published on the manufacturer's product page; ask for this information when ordering.

İntegral products · Product: İntegral UK-PLUS DN20

Novus Digitermo DTL

Novus Digitermo DTL is an ultrasonic series sold on our site in four sizes from DN20 to DN40. We could not find an independent manufacturer data sheet published online for this series; the information below is based on the product information on our site.

• According to the product information on our site: It communicates via wired M-Bus, is used in heating and cooling, has accuracy class 2, its MID approval was obtained in Türkiye and it is manufactured in Türkiye.
• Points to watch: Battery life has not been published. Contact us for the MID certificate and technical data sheet.

Novus Digitermo products · Example product: Novus Digitermo DTL DN20

Which Brand for Which Situation?

The pairings below are not a ranking; in each case they show the technically suitable options.

• New building, wired reading bus planned: All brands on our site have a model with wired M-Bus. In this case the choice is determined by size, cooling requirement and battery life.
• Existing building, difficult to run cables: Wireless wM-Bus reading is more practical. The models offered with a wM-Bus option on our site are the Minol Zenner C5 IUF and C5 ISF. The manufacturer documents of the Calmet PM02, CEM CM-HR and Danfoss SonoSafe 10 also list wireless module options. See wireless heat meter.
• Cooling or fan-coil installation: All brands except the Danfoss SonoSafe 10 have models that also measure cooling; for Minol Zenner, Calmet and CEM the correct version must be specified when ordering. See cooling meter.
• Building entry, boiler room, large diameter: For DN50 and above there are the Minol Zenner IUF (DN50–DN300) and Calmet PM02 (DN50–DN100) options. See large-diameter heat meter.
• Replacing an old meter: The new meter's size, body length (L) and connection thread must be the same as the old one. Even within the same size, lengths can differ: in DN20, the Honeywell EW700, Calmet PM02, Danfoss SonoSafe 10 and Minol Zenner C5 ISF are 130 mm; in DN25, the Honeywell EW700 and Calmet PM02 are 160 mm while the Minol Zenner C5 IUF DN25 model on our site is 260 mm.
• Battery life, spare parts and service continuity: According to manufacturer data, the longest battery life is that of the Danfoss SonoSafe 10 (16+1 years). In the Minol Zenner, Danfoss, Honeywell and Calmet documents, battery replacement and repair are left to authorized service providers; so ask about the manufacturer's service network and spare parts supply in your country. Of the brands on our site, Calmet (Kayseri) and İntegral (Kastamonu) are manufactured in Türkiye.

Checklist for Choosing a Brand

• MID certificate: Ask for the number of the EU type examination certificate and the accuracy class. MID approval covers heat measurement; if cooling is also to be measured, ask whether the manufacturer has a separate national approval for cooling (the Minol Zenner C5 IUF has German approval no. DE-20-M-PTB-0046).
• Compatibility with the reading system: If the building has a wired M-Bus line or a wireless data collector, the new meter must communicate with the same method. M-Bus and wM-Bus are standard protocols; still, verify in advance that the reading software recognizes the meter's data format.
• Encryption key: wM-Bus telegrams can be AES-encrypted (encryption level 5 or 7 on the Minol Zenner C5 IUF and C5 ISF). To transfer encrypted data to the reading system, each meter's key is required; ask for the key list when you receive the meters.
• Sensor: All DN15–DN40 models on our site use a PT1000 temperature sensor pair. The sensor diameter, mounting method (direct immersion or pocket) and cable length must suit your installation.
• Installation point and dimensions: Compare whether the meter is to be installed on the supply or return line, its body length and connection thread with the installation.
• Spare parts: For installation parts such as sensor adapters, see our heat meter spare parts category.
• Re-verification and battery: Heat meters are subject to periodic re-verification under national rules (in Türkiye every 5 years, with the year of stamping counted as the first year); check your local regulations. Consider battery life together with this schedule: a battery with a 7-year life will complete a 5-year re-verification period but may run out before the second period ends. For details, see our re-verification and calibration page and our Heat Meter Battery guide.

You can browse all models in our Heat Meters and ultrasonic heat meter categories. You can find how to read the meter display in our guide How to Read a Heat Meter, and the meaning of the codes on the display in our guide Heat Meter Error Codes. At Novus Energy we also provide a remote meter reading and heat cost allocation service.