The Athletic linked to Fangraphs data for bullpen stats for the first month of the season. The Padres are leading the league with a crazy 1.66 bullpen ERA through the first month (this makes the fact that the Astros scored on the bullpen in two games earlier more impressive).
But the Astros pen is currently ranked as follows:
ERA, FIP and xFIP #3 2.77, 3.05, and 3.45
K/9 #2 10.46
BB/9 #6 3.04
HR/9 #9 0.80
HR/FB #9 8.1%
LOB% #4 79.1%
WAR #5
It is clearly a strength of this team so far. They are 8th in BABIP at .254 but the two teams ahead of them in ERA, the Padres (.236) and Giants (.241) are even more lucky than the Astros are purported to being.