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Hello Thomas, John Cantor and I put together a system for a passivhaus application that involved:

• EmonPi central hub, with CT and ACAC adapter for household electricity consumption
• EmonTH for outside temperature with external DS18B20 (placement important here, good air flow but out of the sun)
• Multiple EmonTH Temp and Humidity room sensors.
• Modified EmonTH for DHT22 Temperature and humidity + CO2 sensor (Titan CO2 sensor, analog output http://www.titanproducts.com/co2-temperature-sensor-196.html) for main living room.
• Pulse counting EmonTH for kamstrup DHW heat meter
• Pulse counting EmonTH for kamstrup space heating heat meter

I would recommend ensuring that you have good start and end manual meter readings from the electricity meter and any heat metering if needed over the measurement period in order to double check the accumulated kwh elec and heat recorded in emoncms.

If you extend the system with heat metering, kamstrup heat meters have the option of either a mbus or pulse output card, Id go for the mbus and either build the mbus reader Im using for the heat pump monitor or use the heat pump monitor once its ready (which could also serve as your central hub): http://openenergymonitor.org/emon/node/11826

The coheating module by Eric AMANN might be useful too: http://openenergymonitor.org/emon/node/6258

Hi Trystan, 

Thanks for the help. Tomas has been helping us to design and install a monitoring system for our house. Our house has been certified as Passivhaus Plus but we want to monitor its actual performance. We have a 9.5kWpeak solar PV system with two inverters. So we want to monitor the output from the inverters (two CT clips) and our import or export to the grid (one CT clip). 

We do not have any wet heating system and are all electric for our heating and hot water - so I am not sure if we need heat meters. I was planning just to measure the electricity used for hot water and heating. We have:

1. A 1kW postheater in the ventilation system - we can put a CT clip on the live wire to the heater to measure power used

2. Four towel warmers and one electric radiator on a single circuit so we can put a CT clip on this circuit to measure power use.

3. Two 3kW immersion heaters attached to Immersun diverters so we can divert electricity we would otherwise export into our hot water tank.

4. One 3kW immersion heater at the top of the hot water that runs off the normal electricity to boost hot water on cloudy days. 

The heating circuits and inverters are in the Store room on the SF so we would need a EmonTX there with 4 clips. The hot water is in the GF Utility Room so we would need the EmonPi with two CT clips there. The electricity meter is in an external cabinet so I was planning to have an EmonTX with two clips there (one for the import/export from the grid and the second for our car charger) this could have an external temperature sensor hung on the north side of the meter cabinet. 

Does this sound reasonable? I guess we could add a hot water meter to measure the hot water we actually use rather than the power going into the tank. 

Thanks for the help.