Losses in district heating pipeline per meter, also possible in percentage?

I have an 8 m long heat pipe from my house to the garage. According to the pipe manufacturer, the district heating pipe has a loss of 5 watts per meter (at 40 degrees supply temperature). What exactly does that mean, preferably expressed as a percentage? Thanks.

You are losing the equivalent of a 40 watt lamp which would be shining continuously. If you convert that into money (electricity costs), it would be about 8-9 euros per month while the line is in operation. Roughly estimated, I would say that is maybe about 4 months per year (depending on where your house is located). So very roughly calculated, you are looking at around 50 euros per year.

The equation is underdetermined; it depends on what output you draw at 40 degrees in the supply line and what output you draw on average over the winter. Do you know roughly how high your heating demand will be p.a. for the building? And how high the connection capacity to the heat network was dimensioned (i.e., in kW)? According to a rule of thumb, you can calculate about 1 kW of average power per 3000 kWh of demand. Suppose you have 12,000 kWh (a moderately renovated single-family house of usual size or from the early 90s) and thus 4 kW heating capacity, and assuming that the 40 ° supply temperature is then reached, that would now be 8 m * 5 W/m = 40 W and, relative to the 4 kW, thus 1% loss.